TWI624088B - Method and system for providing magnetic tunneling junction elements having an easy cone anisotropy - Google Patents

Abstract

A method and system for providing a magnetic junction in a magnetic device is described. The magnetic junction includes a pinned layer, a non-magnetic spacer layer, and a free layer. The non-magnetic spacer layer is between the pinned layer and the free layer. The free layer has magnetic anisotropy, at least a portion of which is biaxial anisotropy. The magnetic junctions are configured such that when a write current is passed through the magnetic junction, the free layer is switchable between a plurality of stable magnetic states.

Description

Method and system for providing magnetic tunneling junction elements with easy cone anisotropy Reference related application

This is a continuation of the U.S. Patent Application Serial No. 12/854,628, the disclosure of which is incorporated herein by reference in its entirety in its entirety in the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire all This is incorporated herein by reference.

Government rights

The present invention is assisted by the U.S. government in accordance with the DARPA award grant/contract HR0011-09-C-0023. The U.S. Government retains certain rights in the invention.

Field of invention

Exemplary embodiments relate to magnetic junctions that can be used in magnetic devices such as magnetic memory, and such devices that use such magnetic junctions.

Background of the invention

Magnetic memory, especially magnetic random access memory (MRAM) due to its high read/write speed potential, excellent durability, non- Depending on the power and low power consumption during operation, it has gradually attracted people's attention. MRAM can store information using magnetic materials as information recording media. One type of MRAM is a spin transfer torque random access memory (STT-RAM). The STT-RAM utilizes a magnetic junction, at least in part by driving current writing through the magnetic junction. Driving a spin-polarized current through the magnetic junction exerts a spin moment on the magnetic moment in the magnetic junction. As a result, a layer having a magnetic moment responsive to the spin moment can be switched to a desired state.

For example, Figure 1 depicts a conventional magnetic tunnel junction (MTJ) 10 when used in conventional STT-RAM. The conventional MTJ 10 is typically placed on a bottom contact 11, using a conventional seed layer 12, and includes a conventional antiferromagnetic (AFM) layer 14, a conventional pinned layer 16, a conventional tunneling barrier. Layer 18, a conventional free layer 20, and a conventional cover layer 22. The jacking point 24 is also shown.

As shown in Figure 1, conventional contacts 11 and 24 are used to drive current in a current vertical plane (CPP) direction or along the z-axis. The conventional seed layer 12 is typically used to assist in the growth of subsequent layers, such as the AFM layer 14, having the desired crystal structure. Conventional tunneling barrier layer 18 is non-magnetic such as a thin insulator such as MgO.

The pinned layer 16 and the conventional free layer 20 are magnetic. It is conventional that the magnetization 17 of the pinned layer 16 is fixed or pinned in a particular direction, typically by an exchange-offset interaction with the AFM layer 14. Although depicted as a simple (single) layer, the conventional pinned layer 16 can include multiple layers. For example, conventional pinned layer 16 can be a synthetic antiferromagnetic (SAF) layer comprising a magnetic layer that is antiferromagnetically or ferromagnetically coupled via a thin conductive layer such as germanium. In such a SAF, a multilayer magnetic layer interposed with a thin layer of tantalum can be used. Also, other versions of the conventional MTJ 10 An additional pinned layer (not shown) separated from the free layer 20 by an additional non-magnetic barrier or conductive layer (not shown) may be included.

The conventional free layer 20 has a changeable magnetization 21. Although depicted as a single layer, the conventional free layer 20 can also include multiple layers. For example, the conventional free layer 20 can be a composite layer that includes a magnetic layer that is antiferromagnetically or ferromagnetically coupled via a thin conductive layer such as germanium. Although shown as being coplanar, the magnetization 21 of the conventional free layer 20 can have perpendicular anisotropy.

In order to switch the magnetization 21 of the conventional free layer 20, a vertical plane (in the z direction) drives a current. When a sufficient amount of current is driven from the top contact 24 to the bottom contact 11, the magnetization 21 of the conventional free layer 20 can be switched to parallel the magnetization 17 of the pinned layer 16. When a sufficient amount of current is driven from the bottom contact 11 to the top contact 24, the magnetization 21 of the free layer can be switched to parallel the magnetization of the pinned layer 16. The difference in magnetic configuration corresponds to different reluctances and thus corresponds to the different logic states of the conventional MTJ 10 (eg, logic "0" and logic "1").

When used in STT-RAM applications, the free layer magnetization 21 of the conventional MTJ 10 is expected to switch at a relatively low current. The critical switching current (J _c0 ) is the lowest current of the very small precession of the free layer magnetization 21 that is unstable around the original direction. For room temperature measurement, this current value is close to the short pulse (1-20 nanoseconds) switching current. For example, J _c0 may be expected to be on the order of a few milliamperes or less. In addition, it is also desirable to switch time quickly. For example, it may be desirable for the free layer 20 to switch within less than 20 nanoseconds. In addition, fast switching times are also expected. In some cases, a switching time of less than 10 nanoseconds is desired. As such, the data is expected to be stored at conventional MTJ 10 at a higher speed and with a sufficiently low critical current.

Although the conventional MTJ 10 can be written using spin transfer and used in STT-RAM, there are still disadvantages. For example, the soft error rate may be higher than expected for a memory with acceptable J _c0 and switching time. The soft error rate is the probability that a cell is not switched when it receives a current at least equal to the typical switching current (i.e., the magnetization 21 of the free layer 20 of the conventional magnetic junction). The soft error rate expectations for the Department of ^10-9 or ^10-9 or less. However, the conventional free layer 20 typically has a soft error rate that greatly exceeds this value. For example, the soft error rate can be a few power magnitudes greater than 10 ^-9 . As a result, it may not be possible to achieve a sufficiently low _Jc and a combination of a fast enough switching time and an acceptable soft error rate.

A variety of conventional mechanisms for improving characteristics including soft error rates have been proposed. For example, complex structures and/or external magnetic fields can be used to assist. However, these conventional solutions have a limited ability to reduce the soft error rate while retaining other characteristics. For example, scalability, energy consumption, and/or thermal stability may be adversely affected by such conventional methods. Therefore, the performance of using the memory of the conventional MTJ is still expected to be improved.

Accordingly, methods and systems for improving the performance of memory based on spin transfer torque are needed. The methods and systems described herein address this need.

Summary of invention

The exemplary embodiment proposes a method and system that can be used to provide a magnetic junction within a magnetic device. The magnetic junction includes a pinned layer, a non-magnetic spacer layer, and a free layer. The non-magnetic spacer layer is between the pinned layer and the free layer. The free layer has a magnetic anisotropy, wherein At least a portion is a biaxial anisotropy. The magnetic junctions are configured such that when a write current is passed through the magnetic junction, the free layer is switchable between a plurality of stable magnetic states.

10‧‧‧Magnetic tunneling junction (MTJ)

11‧‧‧ Knowing the bottom contact

12‧‧‧Learly seed layer

14‧‧‧General antiferromagnetic (AFM) layer

16‧‧‧Study pinned layer

17‧‧‧Knowledge of the magnetization of the pinned layer

18‧‧‧Custom tunneling barrier

20‧‧‧Learn free layer

21‧‧‧The magnetization of the conventional free layer

22‧‧‧Study cover

24‧‧‧Knowledge top point

100, 200, 200', 200", 200''', 200''', 300, 412‧‧ ‧ magnetic junction

102, 202, 202', 202", 202''', 202'''', 302‧‧‧ selective seed layer

104, 204, 204', 204", 204'", 204'''', 304, 360‧‧‧Selectivity Pinning layer

110, 210, 210', 210", 210''', 210'''', 310, 350‧‧‧ pinned layers

120, 120', 220, 220', 220", 220'", 220'''', 320, 330‧‧‧ non-magnetic spacer

130, 130', 130", 230, 230', 230", 230'", 230''', 330‧‧‧ free layers

132, 134, 136, 138‧ ‧ layers

140, 240, 240', 240", 240''', 240'''', 370‧‧ ‧ selective overlay

150, 150’‧‧‧ Line Chart

160, 170, 180, 180' ‧ ‧ energy curve

162, 172, 182‧‧ minimum

164, 174, 186‧‧ points

184‧‧‧ local maximum

212, 212', 216, 216'‧‧‧ Magnetization, ferromagnetic layer

214, 214'‧‧‧ Non-magnetized spacers

232, 232', 236, 236' ‧ ‧ easy magnetization Shaft, ferromagnetic layer

234, 234'‧‧‧ free layer magnetization, non-magnetic spacers

400‧‧‧ Magnetic memory

402, 406‧‧‧Read/Write Row Selection Driver

403‧‧‧

404‧‧‧Word line selection driver

405‧‧‧

410‧‧‧Magnetic storage cells

414‧‧‧Selection device

500‧‧‧ method

502-508‧‧‧Steps

Figure 1 depicts a conventional magnetic junction.

2 depicts an exemplary embodiment of a magnetic junction including a free layer having biaxial anisotropy.

Figure 3 depicts an exemplary embodiment of anisotropic energy for various magnetic junctions.

Figure 4 depicts an exemplary embodiment of anisotropic energy for a magnetic junction.

Figure 5 depicts an exemplary embodiment of a free layer having biaxial anisotropy.

Figure 6 depicts an exemplary embodiment of a free layer having biaxial anisotropy.

Figure 7 depicts an exemplary embodiment of a magnetic junction comprising a free layer having biaxial anisotropy.

Figure 8 depicts another exemplary embodiment of a magnetic junction comprising a free layer having biaxial anisotropy.

Figure 9 depicts another exemplary embodiment of a magnetic junction comprising a free layer having biaxial anisotropy.

Figure 10 depicts another exemplary embodiment of a magnetic junction comprising a free layer having biaxial anisotropy.

Figure 11 depicts a free layer comprising biaxial anisotropy Another exemplary embodiment of a magnetic junction.

Figure 12 depicts another exemplary embodiment of a magnetic junction comprising a free layer having biaxial anisotropy.

Figure 13 depicts an exemplary embodiment of a memory utilizing a magnetic substructure in the memory element(s) of the storage cell(s).

Figure 14 depicts an exemplary embodiment of a method for fabricating a magnetic secondary structure.

Detailed description of the preferred embodiment

The exemplary embodiments relate to magnetic junctions that can be used in magnetic devices, such as magnetic memory, and such devices that use such magnetic junctions. The detailed description is presented to enable those skilled in the art to make and use the invention, which is claimed in the context of the patent application. Various modifications to the exemplary embodiments described herein and their general principles and features are apparent. The exemplary embodiments are primarily described in terms of specific methods and systems presented in the particular embodiments. However, such methods and systems will operate effectively in other applications. Words such as "exemplary embodiment", "an embodiment" and "another embodiment" may mean the same or different embodiments and various embodiments. The embodiments are described in terms of systems and/or devices having certain components. However, the systems and/or devices may include more or less components than those shown, and variations in the configuration and type of components may be made without departing from the scope of the invention. The exemplary embodiments will also be described in terms of a particular method with certain steps. However, the method and system are used to be inconsistent with the exemplary embodiments. And/or additional steps and other methods of steps in a different order can operate effectively. Thus, the present invention is not intended to be limited to the embodiments shown, but the

A method and system for providing a magnetic junction and a magnetic memory using the magnetic junction are described. The exemplary embodiments provide methods and systems for providing magnetic junctions in a magnetic device. The magnetic junction includes a pinned layer, a non-magnetic spacer layer, and a free layer. The non-magnetic spacer layer is interposed between the pinned layer and the free layer. The free layer has magnetic anisotropy, at least a portion of which is biaxial anisotropy. The magnetic junctions are configured such that when a write current is passed through the magnetic junction, the free layer is switchable between a plurality of stable magnetic states.

The exemplary embodiments are described in terms of specific magnetic junctions and the magnetic memory of certain components. Those skilled in the art will readily recognize that the present invention is compatible with the use of magnetic junctions and magnetic memory having other and/or additional components and/or other features not inconsistent with the present invention. The method and system are also described in terms of current understanding of spin transfer phenomena, magnetic anisotropy, and other physical phenomena. As a result, skilled artisans will readily recognize that the theoretical interpretation of the method and system is based on current understanding of spin transfer phenomena, magnetic anisotropy, and other physical phenomena. However, the methods and systems described herein are not dependent on a particular physical interpretation. Skilled artisans will also readily recognize that the method and system are described in terms of a structural structure that has a particular relationship to the substrate. However, those skilled in the art will readily recognize that the method and system are compatible with other structures. Moreover, the method and system are synthesized with certain layers and/or Described as a single integrated vein. However, those skilled in the art will readily recognize that such layers may have other configurations. Moreover, the method and system are described in terms of a magnetic junction and/or a secondary structure having a particular layer. However, those skilled in the art will readily recognize that magnetic junctions and/or secondary structures having additional and/or different layers that are not inconsistent with the method and system can be used. Furthermore, certain components are described as being magnetic, ferromagnetic, and ferrimagnetic. As used herein, the term magnetic may include ferromagnetic, ferrimagnetic, and the like. Thus, as used herein, the terms "magnetic" or "ferromagnetic" include, but are not limited to, ferromagnetic and ferrimagnetic. The method and system are also described in terms of a single magnetic junction and a secondary structure. However, those skilled in the art will readily recognize that the method and system are compatible with the use of magnetic memory having multiple magnetic junctions and using multiple secondary structures. Moreover, as used herein, "coplanar" is a plane that is substantially in the plane of one or more of a plurality of layers of magnetic junctions or parallel to one or more of a plurality of layers of a magnetic junction. Conversely, "vertical" corresponds to a direction that is substantially perpendicular to one or more of the plurality of layers of the magnetic junction.

2 depicts an exemplary embodiment of a magnetic junction 100 for use in a magnetic device such as a magnetic memory such as an STT-RAM. For clarity, Figure 2 is not drawn to scale. The magnetic junction 100 includes a pinned layer 110, a non-magnetic spacer layer 120, and a free layer 130. The pinning layer 104 is also shown, and the pinning layer 104 can be used to fix the magnetization of the pinned layer 110 (not shown). In some embodiments, the pinning layer 104 can be an AFM layer or layers that fix the magnetization (not shown) of the pinned layer 110 by swap-offset interaction. However, in other embodiments, the pinning layer 104 can be Other structures may be omitted or may be used. Moreover, the magnetic junction 100 can include other layers and/or additional layers, such as the selective seed layer 102 and/or the selective cover layer 140. The magnetic junction 100 is also configured to allow the free layer 130 to be switched between stable magnetic states as a write current is passed through the magnetic junction 130. As such, the free layer 130 is switchable using the spin transfer torque.

The pinned layer 110 is magnetic and thus may include one or more of nickel, iron, and cobalt. Although depicted as a single layer, the pinned layer 110 can include multiple layers. For example, the pinned layer 110 can be a SAF that includes a magnetic layer that is antiferromagnetically or ferromagnetically coupled via a thin layer such as ruthenium (Ru). In such SAF, a multilayer magnetic layer interleaved with a thin layer of tantalum or other material can be used. The pinned layer 110 can also be other layers. Although the magnetization is not depicted in Figure 2, the free layer may have a perpendicular anisotropy energy that exceeds one of the de-magnetic energy in the same plane.

The spacer layer 120 is non-magnetic. In some embodiments, the spacer layer 120 is an insulator, such as a tunneling barrier. In such embodiments, the spacer layer 120 can comprise crystalline magnesium oxide that enhances the tunneling magnetoresistance (TMR) of the magnetic junction. In other embodiments, the spacer layer can be a conductor such as copper. In alternative embodiments, the spacer layer 120 can have other structures, such as a layer of particles comprising conductive channels in an insulating matrix.

The free layer 130 is magnetic and thus may include at least one of iron, nickel, and/or copper. The free layer 130 has a changeable magnetization (not shown) that can be switched by spin transfer. This free layer 130 is depicted as a single layer. In other embodiments, the free layer 130 can include other layers. For example, the free layer may be a SAF comprising a ferromagnetic layer interleaved with a non-magnetic layer One or more of them. Alternatively, the free layer 130 can comprise a ferromagnetic layer or other multilayer.

Further, the free layer 130 has magnetic anisotropy. The magnetic anisotropy comprises at least one biaxial component. The magnetic anisotropy may also comprise a uniaxial component. The biaxial component of the magnetic anisotropy can substantially result in an improved soft error rate without adversely affecting characteristics, such as critical switching current _Jc0 . Note that the free layer 130 as a whole, the free layer 130 portion (eg, one or more layers), or some other configuration of the free layer 130 may have biaxial anisotropy.

The effect of biaxial anisotropy can be understood in the lines 150 and 150' of the lines depicted in Figures 3 and 4, respectively. Line diagrams 150 and 150' are for illustrative purposes only and are not intended to reflect a particular magnetic junction. Again, curves 160, 170, and 180 have been offset for clarity. Referring to Figures 2-4, for example, the magnetic anisotropy energy of the free layer 130 can be expressed by a function from a specific direction as follows: E(θ) = K _uni sin ² (θ) + K _bi sin ² (2θ)

K _uni sin ² (θ) item ( "uniaxial item") is a uniaxial magnetic anisotropy corresponds to. The K _bi sin ² (2θ) term ("biaxial term") corresponds to biaxial magnetic anisotropy. If the biaxial term is zero, the free layer 130 will have uniaxial anisotropy. This point corresponds to the uniaxial energy curve 160 of FIG. The energy curve 160 has a minimum value 162 along the easy axis direction. As such, the uniaxial energy curve 160 has a minimum value of 162 at θ=-π, 0, π. In general, the directions are parallel and anti-parallel to the magnetization of the pinned layer 110 (not shown). The initial state of the near zero free layer 130 is shown at point 164. These directions (eg, θ = 0) happen to correspond to the stopping points of the spin transfer torque and the field moment. At a spin transfer torque stop point, the spin polarized current exerts little or no torque on the magnetization of the free layer 130. For uniaxial anisotropy, the spin transfer torque descent point corresponds to the configuration in which the magnetization of the free layer 130 is in equilibrium and aligned with the easy axis of magnetization (θ = 0 and π). As used herein, the easy magnetization axis corresponds to the direction in which the magnetization of the free layer 130 is only stable to uniaxial anisotropy. Since the uniaxial term is magnetized to the free layer 130 at the dwell point, there is a higher probability that the free layer 130 will not switch in response to a critical current application. In this way, the soft error rate for this connection can be higher.

If the uniaxial term is zero, the anisotropy energy for the free layer 130 as in the above embodiment is a biaxial term. The free layer 130 will have biaxial anisotropy. As a result, the energy minimum (the steady state of the free layer 130) will be along and perpendicular to both the uniaxial easy axis directions (θ = 0, π/2, and π). In general, the directions are parallel, perpendicular to, and anti-parallel to the magnetization of the pinned layer 110 (not shown). One of these directions (eg, θ = π/2) happens to be away from the dwell point of the spin transfer torque. However, the remaining two directions (θ = 0, π) are close to the dwell point of the spin transfer torque.

If there is some biaxial anisotropy in addition to uniaxial anisotropy, the uniaxial energy curve 160 is perturbed by the biaxial term (K _bi sin ² (2θ)). The energy curve 170 depicts the energy of the angle of the relatively small biaxial anisotropy. In other words, the absolute value (or amplitude) of biaxial anisotropy is less than the absolute value of uniaxial anisotropy. However, the signs of biaxial anisotropy and uniaxial anisotropy may be the same or different. Due to the introduction of a small biaxial term, the curve 170 is flattened at a minimum value 172 close to -π, 0, and π. The steady state of the free layer 130 near zero is shown at point 174. Since the energy curve 170 is planarized, the initial state of the free layer 130 can be a large expansion without changing the energy barrier that the magnetization must overcome to switch to the opposite state. As such, thermal stability may not be affected. The larger expansion in the steady state of the free layer 130 may correspond to magnetization of the free layer 130 that is more likely to be at an angle from the axis of easy magnetization. In other words, the magnetization of the free layer 130 is more likely to be at an angle other than zero in FIG. As such, the magnetization of the free layer is more likely to be away from the dwell point of the spin transfer torque. As a result, the magnetization of the free layer 130 can be more easily switched by applying a critical switching current.

As the magnitude of the biaxial term (K _bi sin ² (2θ)) in the magnetic anisotropy energy is further increased, the uniaxial energy curve 160 is more disturbed. The energy curve 180 depicts the energy of the angle relative to the larger biaxial anisotropy. The biaxial anisotropy of curve 180 is still less than uniaxial anisotropy. In other words, the absolute value of biaxial anisotropy is still less than the absolute value of uniaxial anisotropy. However, in various embodiments, the signs of uniaxial anisotropy and biaxial anisotropy may be the same or different. Due to the introduction of larger biaxial terms, the curve no longer has a minimum at -π, 0 and π. Instead, the minimum value 182 is an angle from -π, 0, and π. The local maximum 184 is at and near 0, -π, and π. The angle between the easy magnetization axis and the minimum value 182 may be greater than zero but less than π/2. In some embodiments, the angle is at least π/18 and no greater than π/4 (10 degrees - 45 degrees). In some such embodiments, the angle is at least π/9 and no greater than π/6 (20 degrees -30 degrees). As such, the steady state of the magnetization of the free layer 130 can be at or near the angle (ie, the minimum energy at curve 180). The steady state of the free layer 130 near zero is shown at point 186. Since the energy curve 180 has a local maximum 184 at 0, the point 186 is at or near the minimum 182. Figure 4 depicts the energy curve 180' in three dimensions. In the embodiment shown, curve 180/180' is a symmetrically surrounding easy axis (angle is 0). In some embodiments, the free layer 130 magnetization may be at least 10 degrees and no greater than 45 degrees from the uniaxial easy axis. In some of these embodiments, the free layer 130 magnetization may be stabilized in a direction that is at least 10 degrees and no greater than 45 degrees from the uniaxially susceptible axis. The magnetic anisotropy of the free layer 130 may be referred to as cone anisotropy and is a combination of uniaxial anisotropy and biaxial anisotropy. A larger expansion in the initial state of the free layer 130 may mean that the magnetization of the free layer 130 is more likely to be at a small angle or bevel from the axis of easy magnetization. In other words, the magnetization of the free layer 130 is more likely to be at an angle other than zero in FIG. As such, the magnetization of the free layer 130 is more likely to be away from the dwell point of the spin transfer torque.

The introduction of biaxial anisotropy in the free layer 130 improves the switching characteristics of the free layer 130. At near zero, the minimum of the energy curve can be flattened (can be curve 170) or moved away from zero (energy curve 180). The magnetization of the free layer 130 can thus have a stable state that is inclined from the axis of easy magnetization. The magnetization of the free layer 130 can thus be considered to be easier to switch by a rotational or field induced moment. This feature corresponds to a lower soft error rate. This can be true even at high (less than 10 microsecond transition time) data rates. It has also been decided that in some embodiments, this improvement can be substantially achieved without adversely affecting the magnitude of the critical switching current. Furthermore, the thermal stability and symmetry of the magnetic junction 100 can be unaffected adversely. Since the external magnetic field does not require switching the magnetic junction 100, the magnetic junction 100 can be expanded to a higher memory density. The effectiveness and flexibility of the magnetic junction 100 and a memory using the magnetic junction 100 can thus be improved.

Other anisotropy may cause easy taper anisotropy Similar to the aforementioned combination of biaxial and uniaxial anisotropy. Easy cone anisotropy occurs for a free layer having a magnetic moment that is stable at a non-zero angle from the polar axis. In this case, the conventional easy magnetization axis is degenerate into a tapered surface, so that if the magnetization system is at this tapered surface, the energy of the system is unchanged. As such, the free layer 130 can have an energy minimum at a non-zero angle from the polar axis. In particular, a combination of two or more anisotropies with different angular dependence can result in easy cone anisotropy. A total anisotropy energy having an angular dependence of at least one energy minimum at a non-zero angle and a ratio of any two of them may cause easy cone anisotropy. In other words, the total energy as follows can cause easy cone anisotropy.

E _total (θ)=E ₁ (θ)+E ₂ (θ)+E ₃ (θ)+...+E _n (θ), where E _i (θ)/E _j (θ)=f(θ )

E _total (θ) has at least one minimum value at θ0 (0 and the polar axis corresponds to θ = 0. Each E _i (θ), where i = 1, 2, ..., n is θ with θ The total energy of the free layer of an energy term. Similarly, f(θ) is a function that changes with θ. The aforementioned uniaxial and biaxial anisotropy can be regarded as a special case of such easy taper anisotropy. Other energy terms that comply with the aforementioned criteria may also cause easy taper anisotropy. For example words, assuming anisotropy energy of the free layer 130 _{E total (θ) = K 1} sin 2 (θ) + K 2 sin 4 (θ). In the expression, E ₁ (θ) is K ₁ sin ² (θ), E ₂ (θ) is K ₂ sin ⁴ (θ), and f(θ) is (K ₁ /(K ₂ sin ² ( θ)). Two energy terms can be considered as uniaxial terms with a power greater than 1 (with θ dependence rather than 2θ dependence). For example, E ₁ (θ) is the second power (sin ² ) And E ₂ (θ) is the fourth power (sin ⁴ ). This combination has the minimum energy at non-zero θ, provided some restrictions on the K1 and K2 values (especially K1<0, K2> -K1) is satisfied. It always meets the above criteria, so it does have easy taper anisotropy. Similarly, although there are only two, E _total (θ) = K ₁ ^* Sin ² (θ) + K ₄ ^* The total energy of Sin ⁶ (θ) results in an easy taper surface anisotropy. Another embodiment of such easy taper anisotropy is a rhombohedral crystal structure with E _total (θ) = K ₁ ^* Sin ² (θ) + K ₂ ^* Sin ⁴ (θ) + K ₃ ^* Cos (θ) ^* Sin ³ (θ) represents the total energy of the free layer 130. Furthermore, the specific free layer can be due to uniaxial, double A combination of axes, and/or higher power uniaxial anisotropy with easy cone anisotropy. For example, it can be provided with E _total (θ) = K ₁ sin ² (θ) + K ₂ sin ⁴ (θ) + K _uni sin ² (θ) + K _bi sin ² (2θ) of the total anisotropic energy of the free layer 130. This free layer has not only due to the first two higher power terms It is easy to taper anisotropy, and also has the first power uniaxial anisotropy due to the third term and the easy taper anisotropy due to the biaxial anisotropy caused by the last term. The free layer 130 having a total anisotropy energy of two or more has at least a minimum of energy at a non-zero angle, and the ratio of any two of them varies depending on the angle result also results in easy taper anisotropy.

In some embodiments, the dominant origin of the anisotropy term in the total energy _Etotal is the magnetocrystalline anisotropy of the free layer 130. Different magnetocrystalline anisotropies may be caused by different crystal phase structures and with different angular dependence. Similarly, easy cone anisotropy can be considered as at least partial magnetostatic induction. The _{demagnetization} energy (K _demag sin ² θ) of the free layer 130 can be regarded as a uniaxial anisotropy having a negative energy constant K _demag and a dependency on the saturation magnetization M _s . The magnitude of the _{demagnetization} energy K _demag can be controlled by controlling M _s . Therefore, the magnitude of the constant ratio of some of the energies E _total (θ) can be controlled by controlling M _s . Thus, the desired easy taper anisotropy can be achieved. Similarly, easy cone anisotropy can be induced by multiple layers adjoining the free layer. For example, at least one of the above energy terms can be induced by spacing the free layer 130 from the reference layer 110 or an adjacent spacer layer 120 of the cover layer 140. For example, a material such as magnesium oxide can induce a perpendicular anisotropy which contributes to the above total energy, depends on θ, and thus contributes to easy cone anisotropy. In addition, other anisotropies can contribute to total anisotropy energy.

The introduction of easy cone anisotropy can have the benefit of improved spin torque switching. For example, the free layer 130 exhibits improved switching characteristics. Near zero, the minimum of the energy curve can be flattened or removed from 0, similar to curves 170 and 180 depicted in Figures 3-4. The magnetization of the free layer 130 can thus be considered to be easier to switch by a spin transfer torque or a field induced moment. This feature corresponds to a lower soft error rate. This is true even at high (less than 10 microsecond transition time) data rates. This improvement can be achieved substantially without adversely affecting the magnitude of the critical switching current. Furthermore, the thermal stability and symmetry of the magnetic junction 100 can be unaffected adversely. Since the magnetic field 100 can be switched without an external magnetic field, the magnetic junction 100 can be expanded to a higher memory density. The effectiveness and flexibility of the magnetic junction 100 and a memory using the magnetic junction 100 can thus be improved.

The introduction of the easy cone anisotropy and/or biaxial anisotropy improves the characteristics of the free layer 130. There are several ways to get this anisotropy. Figure 5 depicts an exemplary embodiment of a free layer 130' having biaxial anisotropy. In some embodiments, the free layer 130' can also have an easy taper anisotropy as discussed above. A non-magnetic spacer layer 120' is also shown. In the illustrated embodiment, the free layer 130' can have an easy taper anisotropy and/or biaxial anisotropy, which is structural sensing, texture sensing, and/or magnetization sensing. In addition to biaxial anisotropy, the free layer 130 may also have uniaxial anisotropy. For example, if the free layer 130' is to have a structure-induced biaxial anisotropy, the crystallographic energy coefficient (K1=K _bi ) increases in one direction, and the saturation magnetization in a second direction opposite to the first direction. M _s increases. One mechanism for achieving this is shown in Figure 6. Figure 6 depicts an exemplary embodiment of a free layer 130" having biaxial anisotropy. The free layer 130" may also have uniaxial anisotropy. The free layer 130" includes multiple layers. In the illustrated embodiment, four layers 132, 134, 136, and 138 are shown. Other numbers of layers can be used in other embodiments. The layers 132, 134, 136, and 138 The saturation magnetizations M _s1 , M _s2 , M _{s3 ,} and M _s4 are respectively obtained. Similarly, the layers 132, 134, 136, and 138 have biaxial crystal energy coefficients K _bi1 , K _bi12 , K _{bi13 ,} and K _{bi14 , respectively} . As seen in Figure 6, the closer to the nonmagnetic spacer layer M _s increases (not shown in FIG. 6). Likewise, nearer K _bi nonmagnetic spacer layer is reduced. such a multilayer may have biaxial anisotropy. Additionally or in addition to In addition to the aforementioned mechanisms, biaxial anisotropy can be structurally induced in another manner. In other embodiments, the classification of a particular material concentration can be used to achieve a similar effect. For example, a negative K _bi can be to provide biaxial anisotropy. further, some materials are more likely to produce a biaxial anisotropy. for example words, the free layer may include a _{LaSrMnO 3, GaAs, MnAs, MnAl} , Nd 2 Fe14B, Ho 2 Fe14B, NdFeB , Fe, FeCo, YCo ₅ , Ni, ferrite with little or no Co, CoOFe ₂ O ₃ , FeO-Fe One or more of ₂ O ₃ , MnO—Fe ₂ O ₃ , NiO—Fe ₂ O ₃ , MgO—Fe ₂ O ₃ . Thus, the structure of the free layer 130 ′ / 130 ′′ can be tailored to achieve The desired biaxial anisotropy.

In other embodiments, the easy taper and/or biaxial anisotropy may be textured. For example, it is assumed that a magnetic layer having cubic anisotropy is provided. Further, the free layer 130' may be a film having the same plane anisotropy. The combination may have a ^{Asin 2 (θ) + Bsin 2} 2θ + Csin 2 θ of a given energy, wherein A, B and C are coefficients. In this embodiment, the free layer 130" has a biaxial anisotropic combined uniaxial anisotropy. Furthermore, the biaxial anisotropy is permeable to magnetostrictive sensing within the free layer 130'. Thus, the free layer 130'/130" has biaxial anisotropy. As a result, the free layer 130/130' can provide one or more benefits described herein when incorporated into a magnetic junction.

Figure 7 depicts an exemplary embodiment of a magnetic junction 200 that includes a free layer having easy taper and/or biaxial anisotropy. In some embodiments, the free layer can have an easy taper anisotropy. For the sake of clarity, Figure 7 is not drawn to scale. The magnetic junction 200 can be used in a magnetic memory such as an STT-RAM. Magnetic junction 200 is similar to magnetic junction 100 and thus includes a similar structure. The magnetic junction 200 includes selective seed crystals similar to the selective seed layer 102, the selective pinning layer 104, the pinned layer 110, the non-magnetic spacer layer 120, the free layer 130, and the selective cap layer 140, respectively. Layer 202, selective pinning layer 204, pinned layer 210, non-magnetic spacer layer 220, free layer 230, and selective cap layer 240. The layers 210, 220, 230, and 240 have structures and functions similar to those of the layers 110, 120, 130, and 140, respectively. As discussed above, the free layer 230 has biaxial anisotropy. Therefore, the aforementioned benefits can be achieved.

In addition, the free layer 230 has its easy axis of magnetization 232, which is substantially in the same plane. Thus, the perpendicular anisotropy energy does not exceed the non-free layer 230 Demagnetize energy in the same plane. Due to the biaxial anisotropy, the steady state of the free layer magnetization 234 is at an angle θ from the easy magnetization axis 232. The angle θ corresponds to the energy minimum of the energy curve 180. The pinned layer 210 is also shown with its magnetization 212 fixed in the same plane. As such, the perpendicular anisotropy energy does not exceed the non-in-plane demagnetization energy of the pinned layer 210. However, in another embodiment, the magnetization 212 can be in the other direction.

Figure 8 depicts an exemplary embodiment of a magnetic junction 200' comprising a free layer having an easy taper and/or biaxial anisotropy. In some embodiments, the free layer can have an easy taper anisotropy. For clarity, Figure 8 is not drawn to scale. The magnetic junction 200' can be used in a magnetic memory such as an STT-RAM. The magnetic junction 200' is similar to the magnetic junctions 100 and 200 and thus includes a similar structure. The magnetic junction 200' includes a selective seed layer 102/202, a selective pinning layer 104/204, a pinned layer 110/210, a non-magnetic spacer layer 120/220, and a free layer 130/230, respectively. And the selective seed layer 202' of the selective cap layer 140/240, the selective pinning layer 204', the pinned layer 210', the non-magnetic spacer layer 220', the free layer 230', and the selective cap layer 240' . The layers 210', 220', 230' and 240' have structures and functions similar to those of the layers 110, 120, 130 and 140, respectively. Moreover, at least in some embodiments, the pinned layer 204' can be omitted. As discussed above, the free layer 230' has biaxial anisotropy. Therefore, the aforementioned benefits can be achieved.

In addition, the free layer 230' has its easy axis of magnetization 232' which is substantially perpendicular to the plane. Thus, the non-in-plane demagnetization energy of the free layer 230' is less than the perpendicular anisotropy energy. Due to the biaxial anisotropy, the steady state of the free layer magnetization 234' is at an angle θ' from the easy magnetization axis 232. Angle θ' corresponds to The energy minimum of the energy curve 180. The pinned layer 210' is also shown to have magnetization that is fixed perpendicular to the plane. As such, the non-in-plane demagnetization energy of the pinned layer 210' is less than the perpendicular anisotropy energy, however, in another embodiment, the magnetization 212' can be in the other direction.

Figure 9 depicts an exemplary embodiment of a magnetic junction 200" comprising a free layer having biaxial and/or easy taper anisotropy. For clarity, Figure 9 is not drawn to scale. Magnetic junction 200" is available In magnetic memory, such as STT-RAM. The magnetic junction 200" is similar to the magnetic junction 100/200/200' and thus includes a similar structure. The magnetic junction 200" includes a selective seed layer 102/202/202', respectively, similar to the selective nail Tie layer 104/204/204', pinned layer 110/210/210', non-magnetic spacer layer 120/220/220', free layer 130/230/230' and selective cover layer 140/240/240' The selective seed layer 202", the selective pinning layer 204", the pinned layer 210", the non-magnetic spacer layer 220", the free layer 230", and the selective cap layer 240". The layers 210", 220", 230" and 240" have structures similar to those of layers 110/210/210', 120/220/220', 130/230/230' and 140/240/240', respectively. And function. As previously discussed, the free layer 230" has biaxial anisotropy. Thus, the foregoing benefits can be achieved. The easy magnetization axis of the free layer 230" is not shown and can therefore be in a desired direction including perpendicular to a plane or coplanar.

In addition, the pinned layer 210" is a SAF that includes ferromagnetic layers 212 and 216 and a non-magnetic spacer 214. In other embodiments, the pinned layer 210" can include additional layers and/or different layers. The ferromagnetic layer 212 has its magnetization fixed by exchange coupling to the pinning layer 204' or through other mechanisms. Reference layer The 216 series is magnetically coupled to the fixed magnetization layer 212.

Figure 10 depicts an exemplary embodiment of a magnetic junction 200'" including a free layer having biaxial and/or easy taper anisotropy. For clarity, Figure 10 is not drawn to scale. Magnetic junction 200' Can be used in magnetic memory such as STT-RAM. The magnetic junction 200'" is similar to the magnetic junction 100/200/200'/200" and thus includes a similar structure. The magnetic junction 200'" includes a selective seed layer 102/202/202'/202", a selective pinning layer 104/204/204'/204", a pinned layer 110/210/210, respectively. Selective seed layer of '/210', non-magnetic spacer layer 120/220/220'/220", free layer 130/230/230'/230" and selective cover layer 140/240/240'/240" 202'", a selective pinning layer 204'", a pinned layer 210'", a non-magnetic spacer layer 220'", a free layer 230'" and a selective cover layer 240'". 210'", 220'", 230'" and 240'" respectively have similar layers 110/210/210'/210", 120/220/220'/220", 130/230/230'/230 Structure and function of "and 140/240/240'/240". As discussed above, the free layer 230'" has biaxial anisotropy. Therefore, the aforementioned benefits can be achieved. The easy magnetization axis of the free layer 230'" is not shown and thus may be in a desired direction including perpendicular to the plane or the same plane.

In addition, the free layer 230'" is a SAF comprising ferromagnetic layers 232 and 236 and a non-magnetic spacer 234. The ferromagnetic layers 232 and 236 are magnetically coupled. In some embodiments, the layers 232 and 236 are Antiferromagnetic alignment. In other embodiments, the layers 232 and 236 are ferromagnetic aligned. The free layer 230'" may also include additional layers and/or different layers. In various embodiments, one or both of the ferromagnetic layers 232 and 236 comprise biaxial anisotropy. So, reachable Become the benefit discussed here.

Figure 11 depicts an exemplary embodiment of a magnetic junction 200"" including a free layer having biaxial and/or easy taper anisotropy. For the sake of clarity, Figure 11 is not drawn to scale. The magnetic junction 200"" can be used in a magnetic memory such as an STT-RAM. The magnetic junction 200"" is similar to the magnetic junction 100/200/200'/200"/200'" and thus includes a similar structure. The magnetic junction 200"" includes a selective seed layer 102/202/202'/202"/202'", a selective pinning layer 104/204/204'/204"/204'", respectively, Pinned layer 110/210/210'/210"/210'", non-magnetic spacer layer 120/220/220'/220"/220'", free layer 130/230/230'/230"/230'" And a selective cover layer 140"240/240'/240"/240'" selective seed layer 202"", a selective pinning layer 204"", a pinned layer 210"", a non-magnetic Spacer layer 220"", a free layer 230"" and a selective cover layer 240"". The layers 210"", 220"", 230"" and 240"" respectively have similar layers 110/210/210'/210"/210'", 120/220/220'/220"/220 Structure and function of '', 130/230/230'/230"/230'" and 140/240/240'/240"/240'". As discussed above, the free layer 230"" has biaxial anisotropy. Therefore, the aforementioned benefits can be achieved. The easy magnetization axis of the free layer 230"" is not shown and thus may be in a desired direction including perpendicular to the plane or the same plane.

In the illustrated embodiment, the free layer 230"" and the pinned layer 210"" are each a SAF. The pinned layer 210"" includes ferromagnetic layers 212' and 216' and a non-magnetic spacer 214'. The ferromagnetic layer 212' is coupled to the pinning layer 204"" by exchange or through other mechanisms with its magnetization fixed. Reference layer 216' Magnetically coupled to the fixed magnetization layer 214'. The free layer 230"" thus includes ferromagnetic layers 232' and 236' and a non-magnetic spacer 234'. Ferromagnetic layers 232' and 236' are magnetically coupled. In some embodiments, the layers 232' and 236' are antiferromagnetic aligned. In other embodiments, the layers 232' and 236' are ferromagnetic aligned. In various embodiments, one or both of the ferromagnetic layers 232' and 236' comprise biaxial anisotropy. In this way, the benefits discussed here can be achieved.

Figure 12 depicts an exemplary embodiment of a magnetic junction 300 that includes a free layer having biaxial and/or easy taper anisotropy. For the sake of clarity, Figure 12 is not drawn to scale. The magnetic junction 300 can be used in a magnetic memory such as an STT-RAM. The magnetic joint 300 is similar to the magnetic joint 100/200/200'/200"/200'"/200"" and thus includes a similar structure. Magnetic junction 300 includes a selective seed layer 102/202/202'/202"/202'"/202"", selective pinning layer 104/204/204'/204"/204', respectively. /204"", pinned layer 110/210/210'/210"/210'"/210"", non-magnetic spacer layer 120/220/220'/220"/220'"/220"", free Layer 130/230/230'/230"/230'"/230"" and selective cover layer 140/240/240'/240"/240'"/240"" selective seed layer 302, a selection The pinning layer 304, a pinned layer 310, a non-magnetic spacer layer 320, a free layer 330, and a selective capping layer 370. The layers 310, 320, 330, and 370 have similar layers 110/210/210'/210"/210'"/210"", 120/220/220'/220"/220'"/220, respectively. Structure and function of "", 130/230/230'/230"/230'"/230"" and 140/240/240'/240"/240'"/240"". Free layer 330 The easy magnetization axis is not shown and can therefore be tied in a desired direction that is perpendicular to the plane or the same plane.

Magnetic junction 300 also includes an additional non-magnetic spacer layer 340, an additional pinned layer 350, and an additional pinning layer 360. The non-magnetic spacer layer 340 is similar to the non-magnetic spacer layer 320. The additional pinned layer 350 and the optional additional pinned layer 360 are similar to the layers 310 and 304, respectively. As such, the magnetic junction 300 is a double junction. For example, if the non-magnetic spacer layers 320 and 340 are insulating tunneling barrier layers, such as crystalline magnesium oxide, the magnetic junction 300 is a dual MTJ. If the non-magnetic spacer layers 320 and 340 are conductive, the magnetic junction 300 is a dual spin valve. Other configurations of the non-magnetic spacer layers 320 and 340 are also possible. Furthermore, the non-magnetic spacer layers 320 and 340 need not be identical.

The free layer 330 has biaxial anisotropy. Further, the free layer 330 can be similar to any of the free layers 130, 230, 230', 230", 230'" and/or 230"". Therefore, the aforementioned benefits can be achieved at the dual magnetic tunnel junction. For example, magnetic junction 300 can have a lower soft error rate without sacrificing thermal stability, scalability, and low critical switching current.

Various magnetic junctions 100, 200, 200', 200", 200'", 200"" and 300 have been disclosed. Note that various features of the magnetic junctions 100, 200, 200', 200", 200'", 200"" and 300 can be combined. In this way, benefits such as reduced soft error rate, perpendicular anisotropy energy, thermal stability and/or expandability of the magnetic junctions 100, 200, 200', 200", 200'", 200"" and 300 can be achieved. One or more of them.

Furthermore, the magnetic junctions 100, 200, 200', 200", 200'", 200"" and 300 can be used in magnetic memory. Figure 13 depicts such a memory 400 An exemplary embodiment. Magnetic memory 400 includes read/write row select drivers 402 and 406 and word line select driver 404. Note that other components and/or different components may be provided. The storage area of the memory 400 includes magnetic storage cells 410. Each magnetic storage cell includes at least one magnetic junction 412 and at least one selection device 414. In some embodiments, the selection device 414 is a transistor. The magnetic interface 412 can be one of the magnetic junctions 100, 200, 200', 200", 200'", 200"" and 300. While each cell 410 displays a magnetic junction 412, in other embodiments, each cell may provide a different number of magnetic junctions 412. The magnetic memory 400 can thus share the aforementioned benefits, such as a lower soft error rate and a low critical switching current.

FIG. 14 depicts an exemplary embodiment of a method 500 of fabricating a magnetic secondary structure. For the sake of brevity, some steps may be omitted or combined. Method 500 is depicted with the context of magnetic junction 100. However, method 500 can be used on other magnetic interfaces, such as junctions 200, 200', 200", 200'", 200"" and/or 300. Moreover, method 500 can be incorporated into the fabrication of magnetic memory, such as magnetic memory 400. As such, method 500 can be used to fabricate STT-RAM or other magnetic memory. The method 500 can begin after the seed layer 102 and the selective pinning layer 104 are provided.

Through the step 502, the pinned layer 110 is provided. Step 502 can include depositing a desired material at a desired thickness of the pinned layer 110. Again, step 502 can include providing an SAF. Through step 504, a non-magnetized layer 120 is provided. Step 504 can include depositing a desired non-magnetic material including, but not limited to, crystalline magnesium oxide. Additionally, at step 502, a desired thickness of material can be deposited.

Providing a free layer having biaxial anisotropy through step 506 130. In some embodiments, step 506 can be accomplished by depositing multiple layers, SAFs, and/or other structures. Manufacturing is then completed through step 508. For example, an overlay 140 can be provided. In other embodiments, an additional spacer layer 340, an additional pinned layer 350, and a selective additional pinning layer 360 can be provided. In some embodiments, wherein the layers of magnetic junctions are deposited as a stack and then defined, step 508 can include defining magnetic junctions 100, annealing, or otherwise completing the fabrication of magnetic junctions 100. Moreover, if magnetic junction 100 is incorporated into a memory, such as STT-RAM 400, step 508 can include providing a contact, a biasing structure, and other portions of memory 400.

Thus, magnetic junctions 100, 200, 200', 200", 200'", 200"" and/or 300 are formed. Therefore, the benefits of the magnetic junction can be achieved.

Methods and systems for providing a magnetic junction and memory fabricated using magnetic memory components/magnetic secondary structures have been described. The method and system have been described in terms of the illustrated exemplary embodiments, and those skilled in the art will readily recognize that changes can be made to the embodiments, and any changes are within the spirit and scope of the method and system. Therefore, a skilled person can make many modifications without departing from the spirit and scope of the appended claims.

Example 1 According to this example, a magnetic junction for a magnetic device is provided, comprising: a pinned layer; a non-magnetic spacer layer; and a free layer having a magnetic anisotropy energy, the non-magnetic spacer a layer between the pinned layer and the free layer, at least a portion of the magnetic anisotropy energy being an easy taper surface anisotropy energy, the easy taper surface anisotropy energy comprising a plurality of energies having different angular dependence a term such that a ratio of any one of the plurality of energy terms has an angular dependence, the easy taper surface anisotropy energy having at least one energy minimum at a non-zero angle; wherein the magnetic junction The assembly is such that when a write current is passed through the magnetic junction, the free layer is switchable between a plurality of stable magnetic states.

Example 2 This example includes the magnetic junction of Example 1, wherein the plurality of energy terms includes at least one uniaxial anisotropy comprising a term having a power greater than one.

Example 3 This example includes the magnetic junction of Example 2, wherein the uniaxial anisotropy corresponds to an easy axis, wherein the magnetic anisotropy energy is at the non-zero angle from the easy axis of magnetization Having the at least one minimum value.

Example 4 This example includes the magnetic junction of Example 1, wherein at least a portion of the anisotropy terms that result in easy cone anisotropy are crystal induced.

Example 5 This example includes the magnetic junction of Example 1, wherein at least a portion of the anisotropy terms that result in an easy taper anisotropy is magnetostatically induced.

Example 6 This example includes the magnetic junction of Example 1, wherein at least one of the energy terms is induced by an adjacent spacer layer separating the free layer from the reference layer.

Example 7 This example includes the magnetic junction of Example 1, wherein the non-magnetic spacer layer is a tunneling barrier layer.

Example 8 This example includes the magnetic junction of Example 1, wherein the non-magnetic spacer layer is a conductive spacer layer.

Example 9 This example includes the magnetic junction of Example 1, wherein the pinned layer includes a reference layer, a spacer layer, and a fixed magnetization layer, the spacer layer being between the reference layer and the fixed magnetization layer.

Example 10 This example includes the magnetic junction of Example 1, wherein the free layer includes a perpendicular anisotropy energy and a non-in-plane demagnetization energy, the non-in-plane demagnetization energy system being smaller than the vertical Anisotropic energy.

Example 11 This example includes the magnetic junction of Example 8, wherein the pinned layer includes a pinned layer perpendicular anisotropy energy and a fixed layer non-in-plane demagnetization energy, the pinned layer is not in the same The planar demagnetization energy system is smaller than the vertical anisotropy energy of the pinned layer.

Example 12 This example includes the magnetic junction of Example 1, wherein the free layer includes a perpendicular anisotropy energy and a non-in-plane demagnetization energy greater than or equal to the perpendicular anisotropy energy.

Example 13 This one example comprises a sample of the magnetic surface of the 1, further comprising: an additional pinned layer; and an additional non-magnetic spacer layer, the additional nonmagnetic spacer layer located in the free layer and the additional between-pinned layer .

Example 14 This example includes the magnetic junction of Example 13, wherein at least one of the non-magnetic spacer layer and the additional non-magnetic spacer layer comprises crystalline magnesium oxide.

Example 15 According to this example, a magnetic memory is provided, comprising: a plurality of magnetic storage cells, each of the plurality of magnetic storage cells each comprising at least one magnetic junction, the at least one magnetic junction comprising a pinned a layer, a non-magnetic spacer layer, and a free layer having a magnetic anisotropy layer between the pinned layer and the free layer, at least a portion of the magnetic anisotropy is n At least one of the tapered anisotropy energy, the easy cone surface anisotropy energy comprising a plurality of energy terms having different angular dependences such that a ratio of any one of the plurality of energy terms has an angular dependence The easy taper anisotropy energy has at least one energy minimum at a non-zero angle, the at least one magnetic junction being assembled to allow the free layer when a write current is passed through the magnetic junction Switched between multiple stable magnetic states.

Example 16 This example includes the magnetic memory of Example 15, wherein the plurality of energy terms comprise at least one uniaxial anisotropy comprising a term having a power greater than one.

Example 17 This example includes the magnetic memory of Example 15, wherein the uniaxial anisotropy corresponds to an easy magnetization axis and the magnetic anisotropy thereof corresponds to the non-zero angle from the easy axis of magnetization having the at least A magnetic anisotropy energy of a minimum.

Example 18 This example includes the magnetic memory of Example 15, wherein the easy cone anisotropy is at least one of crystal induced, magnetostatically induced, structurally induced, and magnetostrictive.

Example 19 This example includes the magnetic memory of Example 15, wherein the non-magnetic spacer layer is a tunneling barrier layer.

Example 20 This example includes the magnetic memory of Example 15, wherein the pinned layer includes a reference layer, a spacer layer, and a fixed magnetization layer, the spacer layer being between the reference layer and the fixed magnetization layer.

Example 21 This example includes the magnetic memory of Example 15, wherein the free layer includes a perpendicular anisotropy energy and a non-in-plane demagnetization energy, the non-in-plane demagnetization energy system being less than the perpendicular anisotropy energy.

Example 22 This example includes the magnetic memory of Example 15, wherein the free layer includes a perpendicular anisotropy energy and a non-in-plane demagnetization energy greater than or equal to the perpendicular anisotropy energy.

Example 23 This example includes the magnetic memory of Example 15, wherein the magnetic junction further comprises: an additional pinned layer; and an additional non-magnetic spacer layer in which the additional non-magnetic spacer layer is located Pinned between layers.

Example 24 This example includes the magnetic junction of Example 23, wherein at least one of the non-magnetic spacer layer and the additional non-magnetic spacer layer comprises crystalline magnesium oxide.

Claims (10)

A magnetic junction for a magnetic device, comprising: a pinned layer; a non-magnetic spacer layer; and a free layer having a magnetic anisotropy layer in the pinned layer And the free layer, at least a portion of the magnetic anisotropy energy is an easy taper surface anisotropy energy, the easy taper surface anisotropy energy comprising a plurality of energy terms having different angular dependences, such that the plurality of energies A ratio of either of the terms has an angular dependence, the easy taper anisotropy energy having at least one energy minimum at a non-zero angle; wherein the magnetic junction is assembled such that a write current When passing through the magnetic junction, the free layer is switchable between a plurality of stable magnetic states. The magnetic junction of claim 1, wherein the plurality of energy terms comprise at least one uniaxial anisotropy comprising a term having a power greater than one. The magnetic junction of claim 2, wherein the uniaxial anisotropy corresponds to an easy axis, wherein the magnetic anisotropy has the at least one at the non-zero angle from the easy axis Minimum value. The magnetic junction of claim 1, wherein at least a portion of the anisotropy terms that cause anisotropy is at least one of crystal induced, magnetostatic, structurally induced, and magnetostrictive. One. The magnetic junction of claim 1, wherein the pinned layer comprises a reference layer, a spacer layer, and a fixed magnetization layer, wherein the spacer layer is at the reference Between the layer and the fixed magnetization layer. The magnetic junction of claim 1, wherein the free layer comprises a perpendicular anisotropy energy and a non-in-plane demagnetization energy, the non-in-plane demagnetization energy system being smaller than the perpendicular anisotropy energy . The magnetic junction of claim 1, wherein the free layer comprises a perpendicular anisotropy energy and a non-in-plane demagnetization energy, the non-in-plane demagnetization energy system being greater than or equal to the perpendicular anisotropy energy. The magnetic junction of claim 1, further comprising: an additional pinned layer; and an additional non-magnetic spacer layer between the free layer and the additional pinned layer. The magnetic junction of claim 8, wherein at least one of the non-magnetic spacer layer and the additional non-magnetic spacer layer comprises crystalline magnesium oxide. A magnetic memory comprising: a plurality of magnetic storage cells each comprising at least one magnetic junction of any one of claims 1 to 9.