JP3345072B2 - Magnetoresistive element and magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic detection device,
In particular, it relates to a high-sensitivity magnetic detection device.

[0002]

2. Description of the Related Art There are the following conventional techniques for magnetic detection using a magnetoresistive film. I e i
Transaction on Magnetics Vol. 18, No. 2, March (1982) pp. 707-708 (IEEE T
ransaction on Magnetics, Vol.Mag-18, No.2 March (198
2) p.707-708) describes magnetic detection using a Ni / NiO / Ni three-layer film. Journal of the Physical Society of Japan Vol.59 3061
Pp. 3064 describe that metal magnetic films having different magnetic properties are laminated via a non-magnetic film. Physical Review B43, pages 1297-1300 (Physic
al review, B43, 1297-1300), describes the use of a FeMn antiferromagnetic film as a ferromagnetic / nonmagnetic multilayer film. 21 of the 69th meeting of the Japan Society of Applied Magnetics (1991)
~ 26 pages, Fe (30 °) / Cr (9 °) / Fe
Magnetic detection using (30 °) is described. Also,
Japanese Patent Laid-Open Publication No. 2-61572 discloses a magnetic sensor using a ferromagnetic film / non-magnetic film / ferromagnetic film / antiferromagnetic film.

[0003]

Heretofore, in a magnetic detection device having a magnetoresistive element, a magnetoresistive film having sufficient detection sensitivity has not been obtained. In a magnetoresistive multilayer film having a large magnetoresistance effect,
Because the thickness of each layer of the multilayer film is as thin as several tens of degrees or less, there were difficulties in manufacturing a multilayer structure, stability of element characteristics, and controllability due to pinholes and the like.

An object of the present invention is to provide a magnetoresistive film having a highly sensitive magnetic detection capability and a simple element structure for a magnetic detection device having a magnetoresistive element. .

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the magnetic detection sensitivity as a problem in a magnetic detection device having a magnetoresistance effect element.

In the present invention, first, an oxide magnetoresistive film is used as a magnetoresistive film constituting a magnetoresistive element. Here, the oxide magnetoresistive film is a ferromagnetic or weakly ferromagnetic oxide film exhibiting a magnetoresistive effect at a temperature at which the film is used, and has a specific resistance of 1 to 500 mΩcm and a high electric conductivity. Is preferred.

The oxide magnetoresistive film of the present invention also uses a magnetic material which is a simple magnetic substance and exhibits an isotropic or small anisotropic magnetoresistance effect independent of the direction of a magnetic field and current. Here, the isotropic or anisotropic small magnetoresistive effect is a magnetoresistive effect film in which the magnetoresistive effect film is made of a single magnetic material, and is used for detecting a resistance change flowing through the magnetoresistive effect film. Independent of the angle between the current direction and the direction of the magnetic field leaking from the recording medium or magnetic field generator,
Or, it is to exhibit a magnetoresistance effect with little dependence. Heretofore, the magnetoresistance effect of a single-layer magnetic film has shown an anisotropic magnetoresistance effect depending on the angle between the current direction for detecting a resistance change and the direction of a magnetic field leaking from a recording medium or a magnetic field generator. In the anisotropic magnetoresistance effect, when the current direction and the magnetic field direction were parallel, the magnetoresistance ratio was as small as -0.5% or less. (However, a minus sign before the magnetoresistance change rate indicates a decrease in resistance due to application of a magnetic field. The same applies hereinafter.) However, in the isotropic or small anisotropic oxide magnetoresistance effect of the present invention, As a result, a large magnetoresistance effect of -4 to -50% can be obtained regardless of the relative angle between the current direction and the magnetic field direction. As a magnetic substance that is a simple magnetic substance and exhibits a magnetoresistive effect with isotropic or small anisotropy, the current for detecting a change in resistance inside the simple magnetic substance is spin-dependent due to the spin structure of the simple magnetic substance. Desirably, the magnetic material is scattered. Here, the spin-dependent scattering is
Magnetoresistance of a material having two different spin directions, or a metal multilayer film such as a metal ferromagnetic film / metal non-magnetic film / metal ferromagnetic film in which a state having two artificially different spin directions is realized. The scattering of conduction electrons that occurs in the effect and that the degree of scattering of electrons, which are the bearers of the current for detecting a resistance change, due to the spins changes depending on the angle between spins having two different directions. It is. In other words, the change in angle between spins is
This means that a change in magnetoresistance has occurred. Further, as a magnetic material which is a simple magnetic material and exhibits an isotropic or low anisotropy magnetoresistance effect, the simple magnetic material has two different spin directions in its spin structure. A magnetic layer having a spin direction and a magnetic layer having a different spin direction are provided with a magnetic layer /
It preferably has a multilayer structure composed of magnetic layers. A magnetic material having the above characteristics is a canted magnetic material (also called a parasitic ferromagnetic material). Here, in the canted magnetic material (or parasitic ferromagnetic material), the spins of the atoms that are antiferromagnetically aligned are tilted from antiparallel, and two different spin directions are generated. And it is a substance in which spontaneous magnetization corresponding to the angle between the spins appears. The causes of the inclination of the spins from antiparallel are double exchange interaction between spins or anisotropic superexchange interaction, or magnetic anisotropy of a magnetic crystal. Material with the cause double exchange interaction is e.g. _{La 1-x Ca x MnO 3} (x = 0~1),
La _1-x Sr _x MnO ₃ (x = 0 to 1), materials that are responsible for the anisotropic super-exchange interaction include, for example, Fe ₂ O ₃ , MnCO ₃ ,
YFeO ₃ , CrF ₃ , and a material having a cause for magnetic anisotropy include, for example, NiF ₂ . Here, it is particularly preferable to use a canted magnetic material that is caused by the double exchange interaction.

[0008] The oxide magnetoresistive film of the present invention can also be obtained by changing the element composition ratio of the magnetoresistive film.
A magnetic material capable of continuously changing the magnetic transition temperature in a wide temperature range including room temperature is used. Here, the magnetic transition temperature is
This is the temperature at which a magnetic phase transition occurs, and is the critical temperature at which the spin of a magnetic atom changes from disordered to ordered. The magnetic material of the present invention is preferably a magnetic material whose resistance near the magnetic transition temperature contains a large resistance component due to critical magnetic scattering. Here, critical magnetic scattering is a phenomenon in which conduction electrons are unusually scattered due to large spin fluctuations in the critical state.Generally, specific resistance is a temperature at which the resistance component due to critical magnetic scattering becomes maximum. Specific resistance with a peak at a certain magnetic transition temperature-
Shows temperature characteristics. The vicinity of the magnetic transition temperature is a temperature range where the fluctuation of the spin is large, that is, a temperature range where the resistance component due to the critical magnetic scattering is greatly changed by the magnetic field applied to the magnetic material from the outside.
The magnetic material of the present invention is a magnetic material whose resistance value contains a large amount of resistance component due to critical magnetic scattering near the magnetic transition temperature, and is applied to the magnetic material from outside by performing magnetic detection near the magnetic transition temperature. It is preferable to use a magnetic material in which the resistance component due to the critical magnetic scattering changes significantly due to the applied magnetic field, that is, a magnetic material that produces a large magnetoresistance effect.

The oxide magnetic material has the general formula ABO ₃ , where A is a trivalent element or an alkaline earth metal.

B is a magnetic element such as Fe, Co, Ni, Cr and Mn. It is preferable to use those represented by The oxide magnetic material used in the present invention is, specifically,
(La, Ca) ₁ Mn ₁ O _y , (La, Sr) ₁ Mn ₁ O _y , Bi ₁
Mn ₁ O _y , Ba ₁ Fe ₁ O _y , Sr ₁ Co ₁ O _y , (La, A) ₁ B
₁ O _y (A is at least one element of Ba, Sr, Pb and Cd, B is at least one element of Mn and Co), (L
a, A) ₁ B ₁ C ₁ O _y (A is at least one or more rare earth elements, B is at least one or more alkaline earth elements, C
Is at least one of Fe, Co, Mn, Ni, Cr, and Co.
Elements), [(Pr, Nd), (Ba, Sr)] ₁ Mn
₁ O _y , (Bi, Ca) ₁ Mn ₁ O _y , La ₁ (M, Mn) ₁ O
_y (M is at least one element of Co, Ni, Cu, Cr), Gd ₁ (Co, Mn) ₁ O _y , A ₁ (Fe, B) ₁ O _y (A
Is at least one element of Ba, Ca and Sr, and B is M
o, Mn), Bi ₁ Cr ₁ O _y , C
a ₁ Ru ₁ O _y , A ₁ (B, C) ₁ O _y (A is Ba, Ca, S
r, at least one element of Pb, B is Ni, Mn, C
r, at least one element of Fe, C is W, Sb, Mo, U
At least one element of), (Sr, La) ₁ (C, D) ₁
Oy (C is at least one element of Co and Ni, D is N
at least one element of b, Sb and Ta, and y is 2.7
To 3.3. ) Is preferable. Where (A
B) means that it contains at least one of A and B.

The present invention further comprises an oxide magnetoresistive film formed on a substrate, means for flowing a current in the direction of the film surface, and means for detecting a generated voltage. Is to provide a magnetic detection element that detects magnetism by a change in resistance value when a magnetic field is sensed. For this purpose, two current terminals for flowing a current in the longitudinal direction in the film plane and two voltage terminals for detecting a voltage generated at this time are formed in the oxide magnetoresistive film on the substrate. .
Further, it is fixed on a support and connected to a current supply source and a voltage detecting means. When a magnetic field is applied to the oxide magnetoresistive film from the outside in this manner, the voltage generated between the voltage terminals changes according to the magnitude of the applied magnetic field, whereby the magnetic field can be detected. The terminal may have the same current terminal and voltage terminal. The voltage change rate at this time is a value that is at least -50% larger than that of the magnetoresistance effect element according to the related art. The specific resistance of the oxide magnetic material is approximately 10 to 1 at room temperature.
00 milliohm-centimeters, and the absolute value of the generated voltage is at least two orders of magnitude larger than that of the conventional magnetoresistive element. For this reason, a magnetic detection element having a good SN ratio can be obtained. In addition, since the current value during element operation can be reduced to about several tens of microamps, heat generation at the electrode part can be suppressed, and the problem of deterioration of the magnetoresistive film due to heat generation is solved. Is done.

In order to use the present invention in a magnetic recording apparatus, the following is performed. A means for supplying a current and a means for detecting a voltage of the element are connected to a magnetic detection element having at least an oxide magnetoresistive film according to the present invention, and a magnetic signal different from the magnetic detection element is connected. An element for writing on a magnetic recording medium, a so-called recording magnetic head, is placed on the same support. The support allows a drive system controlled by the control unit to write or read magnetic recording at a predetermined position on the magnetic recording medium. Thus, a high-density, large-capacity, small-sized magnetic recording apparatus can be realized.

The magnetic sensing element having at least the oxide magnetoresistive film of the present invention can be used as a recording device of an arithmetic system such as a large computer or a personal computer. Further, it can be used as a recording device of an optical communication system or an optical arithmetic system, or as an arithmetic element.

The magnetic sensing element of the present invention having at least an oxide magnetoresistive film can be used in various systems using a high electromagnetic field generated by an electromagnet, for example, a physical experiment system, an MRI system, a linear motor car system, and the like. The present invention provides a maintenance system for detecting the disappearance or disturbance of a high electromagnetic field due to wear of an electromagnet portion or the like with high sensitivity.

One example of the configuration of the magnetoresistive element of the present invention is a magnetoresistive element in which a single-layer magnetic film is formed on a magnesium oxide substrate and electrodes are arranged on the surface of the magnetic film.
It is desirable that the magnetic film is grown in an epitaxial orientation relationship with the substrate. This is because the magnetic properties of the magnetic film depend on the crystal orientation. The magnetic film of the present invention is, for example, L
a _1-x Ca _x MnO _z is a perovskite-type oxide magnetic material. Where x is the calcium composition and x = 0
.About.0.6. The thickness of the magnetic film is 50 to 5000 °. This configuration realizes high-sensitivity magnetic detection by a large change in magnetoresistance near the magnetic transition temperature.

Second, in the present invention, a three-layered magnetic interaction film consisting of a magneto-resistance effect film / an oxide conductive film / a magneto-resistance effect film is used as a magneto-resistance effect film constituting a magneto-resistance effect element. Here, at least one of the upper and lower magnetoresistive films is an oxide magnetoresistive film composed of an oxide magnetic material, and both of the upper and lower magnetoresistive films are oxide magnetic materials. It may be a film. Here, the oxide conductive film is made of a thin film material that does not have spontaneous magnetization macroscopically, has no magnetic order but has microscopically magnetic spin, or has a magnetic order but macroscopically It is made of an antiferromagnetic material having no spontaneous magnetization. Such a three-layer magnetic interaction film composed of a magnetoresistive effect film / an oxide conductive film / a magnetoresistive effect film means a magnetic layer contained in upper and lower magnetoresistive films via an intermediate oxide conductive film. It realizes high-sensitivity magnetic detection using magnetic interaction acting between elements (for example, manganese, cobalt, iron, etc.).

In the following, the interaction between spins in a single-layer magnetic film is distinguished as a spin-to-spin interaction, and the interaction between spins of two spatially separated magnetic films is distinguished as a magnetic interaction. In the magnetic film, a spin-spin interaction occurs between the spins of the magnetic atoms, and the magnetic film exhibits ferromagnetism and antiferromagnetism. The direction of one spin is “+”,
Assuming that the opposite spin direction is "-", when a spin-to-spin interaction acts such that the spins are aligned in the "+" and "-" directions, this magnetic film becomes antiferromagnetic. When the spin-to-spin interaction acts so as to be aligned in the directions of “+” and “+”, the film exhibits ferromagnetism. However, when the two magnetic films are spatially separated from each other, they serve to transfer the spin-to-spin interaction of one magnetic film to the other magnetic film, such as the intermediate layer in the present invention. Is required. An example of this is a three-layered magnetoresistive film / oxide conductive film / magnetoresistive film, and the magnetic interaction between upper and lower magnetoresistive films via an intermediate oxide conductive film is usually a single layer. It is weaker than the spin-to-spin interaction acting in the magnetic film, and its resistance is greatly changed by the applied magnetic field, so that highly sensitive magnetic detection can be realized. In addition, in a state where a magnetic interaction occurs between the two magnetic films via the intermediate layer, stimuli such as light, pressure, and sound other than an externally applied magnetic field can be used.
The above-mentioned magnetic interaction shows a reaction with high sensitivity. When a current flows in a state where such magnetic interaction occurs, electrons are scattered by spin, and a change in magnetic interaction is detected as a change in electric resistance. The magnetic interaction three-layer film of the present invention realizes high-sensitivity detection for magnetic fields, light, pressure, sound, and the like by utilizing the change in electric resistance.

The intermediate oxide conductive film between the magnetic films is
It is desirable to use a material that has microscopically magnetic atoms and does not macroscopically have spontaneous magnetization, and that has a fluctuation in the spin and charge of the magnetic atoms. For example, there is a material having no magnetic order but having a microscopic magnetic spin, or an antiferromagnetic material having a magnetic order but having no macroscopic spontaneous magnetization. In a magnetic film, when the magnitude of the ferromagnetic force acting on the spin and the magnitude of the antiferromagnetic force are almost the same, when focusing on one atomic spin, this atomic spin is in the “+” direction. , "-" Direction is not determined. Such a state is called a state in which the spin fluctuates. Alternatively, it may be in a state usually called a spin glass. Magnetic interaction 3 in the present invention
The layer film utilizes the fact that such fluctuation of the spin of the intermediate oxide conductive film has a function of transmitting the spin interaction of one magnetic film to the other magnetic film.

The intermediate oxide conductive film is preferably made of an oxide having a perovskite structure. The material used for the intermediate layer is represented by the general formula Ln ₁ B ₂ Cu ₃ O ₇ , A ₂ B ₄ C
_{u 3 O 10, A 2 B} 3 Cu 2 O 8, A 1 B 4 Cu 3 O 8, A 1 B
₃ Cu ₁ O ₁₁ , M _2-x N _x Cu ₁ O ₄ (where A is Tl, B
i, at least one element of Pb. B is at least one kind of alkaline earth metal. M is one of La and Nd. N is any one element of Ce or alkaline earth metal. Ln is any one of Y, rare earth metal and trivalent element. w is 0.05 to 1.00. ) Is preferably used. Further, specifically, the material used for the intermediate layer is (La _1-x M _x ) Cu ₂ O ₄ (M
Is at least one element of Ba, Ca and Sr), La ₁ B
a ₂ Cu ₃ O ₇ , La ₂ NaCuO ₄ , Bi _0.1 La _1.8 Sr
_0.1 CuO, La ₂ CuO ₄ , La ₂ Ba ₃ LuCu ₆ O, Y
Ba ₂ Cu ₃ O ₇ , Y ₂ Ba ₄ Cu ₈ O ₂₀ , Yb ₂ Ba ₄ Cu ₇ O
₁₅ , Bi ₂ Sr ₂ CuO ₆ , Bi ₂ Sr ₂ Ca ₁ Cu ₂ O ₈ ,
Bi ₂ Sr ₂ Ca ₂ Cu ₃ O ₁₀ , Bi ₂ Sr ₂ Ca ₃ Cu _{4
O 12, Ba (Pb 1-} x Bi x) O 3, (Ba 1-x K x) BiO 3,
(Bi _1-x Pd _x ) ₂ Sr ₂ Ca ₂ Cu ₃ O, B
i ₂ Sr _2.6 Nd _0.4 CuO ₈ , Tl ₂ Ba ₂ CuO ₆ , Tl ₂
Ba ₂ Ca ₁ Cu ₂ O ₈ , Tl ₂ Ba ₂ Ca ₂ Cu ₃ O ₁₀ , Tl
₁ Ba ₂ Ca ₁ Cu ₂ O ₆ , Tl ₁ Ba ₂ Ca ₃ Cu ₄ O ₈ , Tl ₁ B
a ₃ Ca ₂ Cu ₄ O ₁₀ , Tl ₁ Sr ₂ Cu ₃ O, (Tl _0.5 Pb _0.5 ) S
r ₂ Ca ₂ Cu ₃ O ₈ , Nd _1.6 Sr _0.2 Ce _0.2 CuO ₄ , Pb
₂ Sr ₂ Y _0.5 Ca _0.5 Cu ₃ O ₈ , (Tl _0.75 Bi _0.25 )
_1.3 (Sr _0.5 Ca _0.5 ) _2.7 Cu ₂ O ₈ (where x is 0.0
5 to 1.0. ) Is preferable. here,
(AB) means that at least one of A and B is included.

Further, the intermediate layer is preferably a substance which exhibits superconducting properties when the temperature of the material used for the intermediate layer is lowered. The present inventors have considered that examining the interaction between an oxide superconductor and a magnetic body when approaching it is important in clarifying the mechanism of the manifestation of high-temperature superconductivity, and have been conducting research so far. . As a result, L, which is a manganese-based oxide magnetic material having a perovskite structure,
a _1-x Ca _x MnO _z (LCMO) and La _1-x Sr _x Mn
O _z (LSMO) and the oxide high-temperature superconductor YBa ₂ Cu ₃
O _y (YBCO) has some limited magnetism (x = 0.2
It has been found that a peculiar proximity effect that a superconducting current flows in a magnetic material occurs only in the region of 0.3). This phenomenon (proximity effect) can be said to be a new phenomenon in the following three points.

(1) A superconducting current flows through a barrier layer far exceeding the coherent length.

(2) When a barrier layer having semiconductor-like electric characteristics is sandwiched between oxide superconductors, the junction resistance exhibits a metallic behavior.

(3) Ferromagnetic and superconducting currents coexist.

As the inventors proceed with research to elucidate this peculiar phenomenon, a magnetic interaction has already occurred between the oxide superconductor and the oxide magnetic material even at room temperature. Therefore, it has been found that the junction resistance exhibits metallic characteristics. Based on the knowledge obtained by this discovery, a three-layer magnetic interaction film of the present invention was obtained. In order to facilitate the formation as an element, the thickness of the intermediate layer is 100 to
Preferably, it is as thick as 2500 °. Oxide high temperature superconductor (YBCO) is an oxide conductive material that can be formed in such a large thickness. And this is the intermediate film
This is an effect of using a material having the above-described spin fluctuation.

On the other hand, as the magnetic material sandwiching the intermediate layer, an oxide magnetic material is preferably used, and particularly, an oxide magnetic material having a perovskite structure is preferably used.
Here, the oxide magnetic material is represented by the general formula ABO ₃ where A
Is a trivalent element or an alkaline earth metal.

B is a magnetic element such as Fe, Co, Ni, Cr and Mn. It is preferable to use those represented by The oxide magnetic material used in the present invention is, specifically,
(La, Ca) ₁ Mn ₁ O _y , (La, Sr) ₁ Mn ₁ O _y , Bi
₁ Mn ₁ O _y , Ba ₁ Fe ₁ O _y , Sr ₁ Co ₁ O _y , (La,
A) ₁ B ₁ O _y (A is at least one element of Ba, Sr, Pb and Cd, B is at least one element of Mn and Co), (La, A) ₁ B ₁ C ₁ O _y (A is At least one or more rare earth elements, B is at least one or more alkaline earth elements, C is at least one element of Fe, Co, Mn, Ni, Cr, Co), [(Pr, Nd), (Ba, Sr)] ₁ M
n ₁ O _y , (Bi, Ca) ₁ Mn ₁ O _y , La ₁ (M, Mn) ₁ O _y
(M is at least one element of Co, Ni, Cu, Cr), Gd ₁ (Co, Mn) ₁ O _y , A ₁ (Fe, B) ₁ O _y (A is at least one _element of Ba, Ca, Sr) Element, B is Mo,
At least one element of Mn), Bi ₁ Cr ₁ O _y , Ca ₁
Ru ₁ O _y , A ₁ (B, C) ₁ O _y (A is Ba, Ca, Sr, P
b is Ni, Mn, Cr, F
e, C is at least one element of W, Sb, Mo, U), (Sr, La) ₁ (C, D) ₁ O _y (C
Is at least one element of Co and Ni, and D is Nb, S
b is at least one element of Ta, and y is 2.7 to 3.3.
And ) Is preferable. Here, (AB) means that at least one of A and B is included.

Further, the magnetic interaction three-layer film of the present invention is characterized in that a coupling layer formed of an oxide conductive film having a perovskite structure is provided between the magnetic films. Here, the coupling layer is an intermediate layer that functions to transmit the spin state of one magnetic film to the other magnetic film so that magnetic interaction occurs between the magnetic films. The oxide conductive film having a perovskite structure, which is a coupling layer, used in the present invention has spin fluctuations. The present inventors have concluded that an oxide superconductor can be used as the above-mentioned coupling layer by using a Mn-based oxide magnetic material La _1-x (Sr, Ca) _x MnO ₃ as a barrier layer and using YBa ₂
In a process of studying the proximity effect that a superconducting current flows through a thick and ferromagnetic barrier layer having a thickness of 5000 ° in the junction of a three-layer structure sandwiching Cu ₃ O _y (YBCO), this was found. This phenomenon includes La _1-x (Sr,
The spin state of Ca) _x MnO ₃ is closely related.
YBa ₂ Cu ₃ O _y / La _0.8 Sr _0.2 MnO ₃ (LSMO)
/ YBa ₂ Cu ₃ O _y Three-layer film and single-layer La _0.8 Sr _0.2 Mn
In order to investigate the difference in the spin state of Mn in the O ₃ film, the temperature dependence of the ferromagnetic resonance (FMR) peak width was examined. The following remarkable differences were observed between the ferromagnetic resonance peak widths of the two. The LSMO single-layer film shows almost no change in temperature, but the ferromagnetic resonance peak width of the three-layer film strongly depends on the temperature and shows a maximum around 150K. The half width of the peak represents the magnitude of spin fluctuation, and is a result showing that the dynamic properties of spin are changed by stacking the oxide magnetic material with the oxide superconductor. is there.
The present invention is based on the properties of the spin state.

Further, the magnetic interaction three-layer film of the present invention has a three-layer structure in which an oxide conductive film is sandwiched by a magnetoresistance effect film, and means for applying a current to the magnetic interaction three-layer film. And means for detecting a voltage generated therefrom. The magnetic interaction three-layer film is a three-layer film in which an oxide superconductor film is sandwiched between oxide magnetic films. Conventionally, an element having a three-layer structure in which a non-superconducting layer having a thickness of about several tens of angstroms is sandwiched between superconductors has been known as a Josephson element. It has a structure sandwiched between non-superconductors, and is completely different from this both structurally and in principle. In particular, in the present invention, unlike the Josephson element, at a temperature higher than the superconducting transition critical temperature where the oxide superconductor exhibits superconducting properties,
It is characterized by utilizing characteristics of a superconductor. In particular, it can be used at room temperature.

The magnetic interaction three-layer film of the present invention comprises a three-layer film comprising an oxide conductive film sandwiched between magnetoresistive films, means for applying a current to the three-layer magnetic interaction film, And a means for externally applying energy. The means for supplying a current to the magnetic interaction three-layer film is a constant current source capable of flowing a constant current, and supplies a current through an electrode made of gold or silver. The voltage generated at this time is monitored by a voltmeter. The terminal for detecting the voltage and the terminal for supplying the current may be the same. When energy such as electromagnetic waves, magnetic fields, light, sound, and pressure is externally applied to the three-layer magnetic interaction film, the spin state changes with high sensitivity. Since this change can be read as a change in voltage, it can be used as a highly sensitive detection element. Further, a usage method utilizing an electromagnetic wave generated when a current is applied is also possible.

Further, the present invention provides a three-layer magnetic interaction film composed of a magnetoresistive film, an oxide conductive film and a magnetoresistive film formed on a substrate, means for flowing a current through the film, and detecting a generated voltage. A magnetic sensing element for detecting magnetism by a change in resistance value when the magnetic interaction three-layer film senses a magnetic field. When the three-layer magnetic interaction film is used as a magnetic sensing element, it is used as follows. In the magnetic interaction three-layer film, an electrode for supplying a current to the upper magnetoresistive effect film is provided and connected to a means for supplying a current. Also,
Further, an electrode for detecting a voltage generated in the magnetic interaction three-layer film and a means for detecting the voltage are connected. When a magnetic field parallel to the film surface is applied to the device, the generated voltage changes due to the magnetoresistance effect. By monitoring the generated voltage, it can be used as a magnetic detection element.

Further, the present invention provides a three-layered magnetic interaction film composed of a magnetoresistive film, an oxide conductive film and a magnetoresistive film formed on a substrate, and means for flowing a current in the direction of the film surface. Means for detecting the generated voltage.
An object of the present invention is to provide a magnetic detection element that detects magnetism by a change in resistance value when a layer film senses a magnetic field. To this end, two current terminals for flowing a current in the longitudinal direction in the film plane and two voltage terminals for detecting a voltage generated at this time are formed in the magnetic interaction three-layer film on the substrate. . Further, it is fixed on a support and connected to a current supply source and a voltage detecting means. When a magnetic field is externally applied to the magnetic interaction three-layer film in this manner, the voltage generated between the voltage terminals changes according to the magnitude of the applied magnetic field, and the magnetic field can be detected. The terminal may have the same current terminal and voltage terminal. At this time, the voltage change rate is a value that is at least -40% larger than that of the conventional magnetoresistive element by one digit or more. The specific resistance of the oxide magnetic material is approximately 1 to 100 milliohm-cm at room temperature, and the absolute value of the generated voltage is about two orders of magnitude larger than that of the conventional magnetoresistive element. For this reason, a magnetic detection element having a good SN ratio can be obtained. Also, since the current value during the operation of the element can be reduced to about several tens of microamps, it is possible to suppress heat generation at the electrode portion, and to solve the problems of deterioration of the magnetoresistive film due to heat generation. You.

A conventional magnetoresistive head, which is a read / write separation type head for the purpose of increasing the density and capacity of a magnetic recording / reproducing apparatus, is provided with uniaxial magnetic anisotropy in the in-plane direction of the ferromagnetic thin film. In such a case, when an external magnetic field is applied perpendicularly to the film surface, the phenomenon that the resistance of the element changes, that is, a so-called “magnetoresistive effect” is used. The conventional magnetoresistive head has a problem that it is susceptible to so-called Barkhausen noise, which is generated when the domain wall moves when the direction of magnetization in the magnetic film is different. Further, a metal ferromagnetic material such as permalloy (Ni-Fe) is mainly used for a ferromagnetic film used for a conventional magnetoresistive head, that is, a magnetoresistive film, and these metal magnetic materials have a specific resistance. Since it is very small, several tens of micro-ohm centimeters, to obtain a high reproduction output, the thickness of the magnetoresistive film of the element must be extremely thin, less than several hundred angstroms, or the current flowing through the element should be as small as possible. Need to be bigger. However, it is difficult to manufacture such a thin film having a small thickness, and there is a problem in that the sensitivity decreases due to an increase in coercive force due to a pinhole in the film. In addition, flowing a large current has a problem that deterioration of the element is accelerated due to heat generation or the like.

In order to solve the above problem, there has been proposed a magnetic sensing element utilizing a giant magnetoresistance effect which is a phenomenon different from the above-described conventional single-layer magnetic film magnetoresistance effect. The giant magnetoresistance effect refers to a ferromagnetic material / non-magnetic material /
This is a phenomenon in which an extremely large magnetoresistance effect appears in a three-layer film such as a ferromagnetic material or a multilayer film composed of a ferromagnetic / non-magnetic material. This phenomenon is said to occur because the upper and lower ferromagnetic materials interact magnetically via the nonmagnetic layer. However, unless the thickness of the nonmagnetic layer is reduced to several tens angstroms or less, the giant magnetoresistance effect does not occur, and it is difficult to control the element characteristics due to pinholes and the like. On the other hand, in the magnetic interaction three-layer film of the present invention, the thickness of the intermediate oxide conductive film can be as large as 500 to 2500 °, so that device characteristics are not disturbed by pinholes or the like.

Further, a ferromagnetic tunnel junction element is a magnetic detection element based on a principle different from the above-described magnetic detection element. This is a ferromagnetic thin film sandwiched between extremely thin insulators having a thickness of several tens of angstroms, and can be used as a high-sensitivity and high-output magnetic detecting element. Since the ferromagnetic tunneling phenomenon occurs only at extremely low temperatures, it has been difficult to apply it as a magnetic detection element. However, according to the present invention, such a problem is solved, and magnetic detection at room temperature is also possible. .

As the inventors proceeded with research on the mechanism of high-temperature superconductivity, the inventors found that the distance between an oxide superconductor having a perovskite structure and an oxide magnetic material was as long as 1.0 μm or more. It has been discovered that magnetic interaction works and that this magnetic interaction also works at temperatures higher than the superconducting transition critical temperature at which the superconductor transitions to the superconducting state. The present invention makes it possible to realize a high-sensitivity magnetic detection element and a high-density, large-capacity magnetic recording apparatus using the same by using the above magnetic interaction.

The present invention also relates to a magnetic recording / reproducing apparatus for reading a magnetic signal recorded on a magnetic recording medium, comprising a magnetic detecting element having a three-layer film of magnetic interaction, which is recorded on the magnetic recording medium. And a magnetic recording device for reading the magnetic signal. When the magnetic sensing element is brought close to the magnetic recording medium on which information is recorded, the detection voltage of the magnetic sensing element changes due to the magnetic field from the magnetic recording medium, and the information written on the magnetic recording medium can be read.

The present invention also relates to a method of using a magnetic interaction element having a superconducting film between oxide magnetic films, wherein the magnetic interaction element is used at a temperature higher than the superconducting transition critical temperature of the superconductor. It provides a method of use.

The magnetic interaction element of the present invention can be used as a recording device of an arithmetic system such as a large computer or a personal computer. Further, it can be used as a recording device of an optical communication system or an optical arithmetic system, or as an arithmetic element.

In order to use the present invention in a magnetic recording apparatus, the following is performed. A means for supplying a current to the magnetic detection element according to the present invention and a means for detecting a voltage of the element are connected, and an element for writing a magnetic signal different from the magnetic detection element to a magnetic recording medium, a so-called element. The recording magnetic head is placed on the same support. The support allows the drive system controlled by the control unit to write or read magnetic recording at a predetermined position on the magnetic recording medium. As a result, a high-density, large-capacity and small-sized magnetic recording device can be realized.

When the three-layer film according to the present invention is used for a device, it is desirable to use the film at a temperature higher than the superconducting transition critical temperature of the superconductor. This is because a unique magnetic interaction found by the inventors occurs in this temperature range. By using the present invention at the above temperature,
It is possible to obtain a magnetic detection element with a high detection sensitivity and a high output than ever before.

The magnetic sensing element of the present invention having at least an oxide magnetoresistive film can be used in various systems using a high electromagnetic field created by an electromagnet, for example, a physical experiment system, an MRI system, a linear motor car system, and the like. The present invention provides a maintenance system for detecting the disappearance or disturbance of a high electromagnetic field due to wear of an electromagnet portion or the like with high sensitivity.

When the oxide magnetic film and the oxide superconducting film are laminated to form a three-layer laminated film, a sputtering method, an ion beam sputtering method, a vacuum deposition method or the like is used to form a titanium film. It is formed on a strontium acid single crystal substrate, a magnesium oxide single crystal substrate, a zirconium oxide single crystal substrate, a glass substrate, a silicon single crystal substrate, a gallium arsenide single crystal substrate, a gadolinium gallium garnet single crystal substrate, or the like. At this time, the thickness of the superconducting layer is desirably 100 Å or more. Further, it is desirable that each magnetic film and each superconducting film are grown in an epitaxial orientation relationship with each other. This is because the strength of the magnetic interaction depends on the crystal orientation. 3
When forming a layer film, the substrate temperature should be 500 to 650 ° C.
The temperature is set to the optimal value between the _two and the oxidizing atmosphere (O ₂ , O ₃ ,
N ₂ O) is produced. After film production,
₂ Introduce gas and cool naturally. When a sputtering method is used, a sintered body target having a predetermined composition ratio is used. When a vacuum evaporation method is used, a metal or an alloy deposition source having a predetermined composition ratio is used. An example of the configuration of the magnetoresistive element of the present invention is a magnetoresistive effect in which a magnetic film / conductive oxide film / three-layer magnetic film is formed on a magnesium oxide substrate and electrodes are arranged on the upper magnetic film surface. Element. The magnetic film is La _1-x
A Ca _x MnO _z perovskite oxide magnetic material,
The oxide conductive film is a YBa ₂ Cu ₃ O _y perovskite-type oxide conductor. Here, x is a calcium composition, and x = 0 to 0.6. The thickness of the magnetic film is 50 to 5000
、, and the thickness of the oxide conductive film is 100 to 2500Å.
It is. This configuration realizes high-sensitivity magnetic detection by a large change in magnetoresistance near the magnetic transition temperature.

[0043]

According to the magnetic detecting device of the present invention,
It has a simple element structure and realizes highly sensitive magnetic detection.

That is, the magnetoresistive film of the present invention is composed of an oxide magnetoresistive film using an oxide magnetic material. The current direction for detecting a change in magnetoresistance and the direction of a magnetic field leaking from a recording medium or a magnetic field generator. It is a magnetic material that exhibits an isotropic magnetoresistance effect that is independent of temperature and that can continuously change its magnetic transition temperature over a wide temperature range including room temperature by continuously changing the element composition of the film. And

This element is arranged close to the recording medium or the magnetic field generator, and the magnitude of the magnetic field applied from the recording medium or the magnetic field generator to the magnetoresistive element is detected as a change in the magnetoresistance of the magnetoresistive film. I do. When the magnetoresistive element is operated near its magnetic transition temperature, the magnetoresistive element exhibits a magnetoresistance change of −50% or more, and can realize high-sensitivity magnetic detection.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment in which at least the oxide magnetoresistive film of the present invention is used as a magnetic detecting element in a magnetic recording / reproducing apparatus having a recording / reproducing separation type head. The read / write separation head includes a read head using the magnetoresistive element of the present invention, an inductive write head, and a shield portion for preventing the read head from being disrupted by a leakage magnetic field. The head is composed of a reproducing head comprising a lower shield 32, an oxide magnetoresistive film 10, an electrode 20, and an upper shield 31 on a substrate 40;
2. A recording head including an upper magnetic film 51 and a coil 60 for applying a magnetomotive force to the upper magnetic film 51 is formed. The head writes a signal on the recording medium and reads a signal from the recording medium. By fabricating an inductive recording head at a low temperature after fabricating an oxide magnetoresistive film at a high temperature of 500 to 600 ° C., it is possible to reduce disturbance of magnetic characteristics due to heat and stress of a recording / reproducing separation type head.

FIG. 2 is a conceptual diagram of a reproducing portion of a magnetic recording / reproducing apparatus using a magnetoresistive element having at least an oxide magnetoresistive film according to the present invention. A magnetoresistive effect film (or oxide magnetoresistive effect film / oxide conductive film / oxide magnetoresistive effect film three-layer film) 10 and an electrode 20 are formed on a base 40, and are formed on a disk disk having a recording medium. Reproduction is performed by positioning on and close to. A feature of the present invention is that at least an oxide magnetoresistive film is used for the magnetoresistive element. With such a configuration,
The signal magnetically recorded on the recording medium reaches the magnetoresistive film 10 as a leakage magnetic field 80 on the medium, and reaches -40 to-.
A high-sensitivity reproduction output can be obtained by a large magnetoresistance effect of 50%.

FIG. 3 is a conceptual diagram showing the configuration of a magnetic recording / reproducing apparatus according to the present invention. Disk disk 71 having recording media on both sides
Is rotated by the spindle motor 75, and the actuator 7
3, the head slider 72 is guided on the track of the recording medium. The read head and the recording head formed by the magnetoresistive element formed on the head slider move relatively close to the recording medium by this rotation, and write or read signals sequentially. The recording signal is sent to the signal processing system 74.
, The data is recorded on a medium by a recording head, and the output of the reproducing head is read as a recording signal via a signal processing system 74. Furthermore, when the reproducing head is moved onto a desired recording track, the position of the track can be detected by using the high-sensitivity output from the reproducing head of the present invention, and the actuator can be controlled to position the head slider. it can.

[0049] of the present invention, the magnetoresistance effect film is a component of the magnetoresistive element, for example, a La _1-x Ca _x MnO _z magnetic film (hereinafter abbreviated as LCMO). FIG. 4 shows the spin structure of LCMO. LCMO has a perovskite-type crystal structure, and its spin structure is such that manganese spins are ferromagnetically aligned in the c-plane and antiferromagnetic between the c-planes via the non-magnetic La and Ca-O layers. It is something which is arranged in order. That is, the LCMO is a simple magnetic substance, and the Mn-O surface having spin and the Ln and Ca-O surfaces having no magnetism are sequentially laminated, and the spins of the adjacent Mn-O surface are antiparallel to each other. This is a system having a multilayer structure composed of a magnetic layer and a non-magnetic layer. In addition, the magnetization of LCMO appears when the manganese spins arranged antiferromagnetically tilt due to double exchange interaction caused by the exchange of electrons between manganese ions. The magnitude of the emerged magnetization corresponds to the angle between the manganese spins oriented in different directions. The smaller the angle between the spins, the greater the magnetization.

The LCMO film, which is a component of the magnetoresistive element of the present invention, is made of MgO (100) having a thickness of 0.5 mm and a square of 10 mm on a side by ion beam sputtering.
The substrate was formed on a single crystal substrate at a substrate temperature of 585 ° C. under which the magnetic film was c-axis oriented. The target for sputtering has a diameter of 6 inches and a thickness of 5 mm.
A sintered body composed of manganese and oxygen was used. A xenon ion beam was used as the ion beam for sputtering, and the atmosphere gas pressure when producing the magnetic film was xenon gas pressure of 0.10 mTorr.
r, the oxygen gas pressure is 0.15 mTorr. Table 1 shows details of the conditions for forming the magnetic film.

[0051]

[Table 1]

The crystal structure and orientation of the produced LCMO film were evaluated by X-ray diffraction. According to the result of X-ray diffraction, L
The CMO film was a c-axis oriented film, and the c-axis length was 7.80 ° at a constant value independent of the film thickness. The resistivity-temperature characteristics and the magnetoresistance effect characteristics of the LCMO film were measured by a four-terminal method, and the magnetic characteristics were measured by a vibrating sample magnetometer. The relationship between the direction of the magnetic field and the direction of the current for detecting a change in the magnetoresistance when measuring the magnetoresistive effect characteristics is determined by applying a magnetic field in the film plane so that the magnetic field direction is parallel to the current direction (H _‖ ), and When a magnetic field is applied and the direction of the magnetic field is perpendicular to the direction of the current (H _⊥ ),
There are two ways. FIGS. 5A and 5B show examples of the temperature dependence of the magnetization and specific resistance of the as-deposited LCMO film manufactured. As can be seen from FIG. 5, the specific resistance has a maximum value near the magnetic transition temperature. In the vicinity of the magnetic transition temperature, the specific resistance takes a maximum value because conduction electrons undergo an abnormally large critical magnetic scattering due to large spin fluctuations in the critical state. FIG. 6 shows the magnetic field dependence of the magnetoresistance effect of the as-deposited LCMO film at 4.2 K and 200 K for two cases where the relationship between the magnetic field direction and the current direction is different. As shown in FIG.
The magnetoresistive effect of the MO film is as follows: 4.2K having a relatively small magnetoresistance change and 200K having a large magnetoresistance change.
In either case, the magnetic field of 1 Tesla did not saturate, and an isotropic magnetoresistance effect independent of the angle between the magnetic field direction and the current direction was obtained. FIG. 7 shows an example of the temperature dependence of the magnetoresistance effect of the as-deposited LCMO film. Like the specific resistance, the magnetoresistance effect has a maximum value of -50% near the magnetic transition temperature.
You can see that The maximum value of the magnetoresistance effect near the magnetic transition temperature is in the temperature region where the spin fluctuation is large near the magnetic transition temperature, and the resistance component due to critical magnetic scattering is given by the magnetic field applied to the magnetic material from the outside. This is because the temperature range changes greatly. FIG. 8 shows the temperature dependence of the magnetoresistive effect of an annealed LCMO film obtained by subjecting an as-deposited LCMO film having a thickness of 3000 ° to oxygen annealing at 580 ° C. for 2 hours in an oxygen atmosphere. The magnetic transition temperature of the annealed LCMO film is room temperature, and the magnetoresistance ratio has a maximum value of −15% at room temperature.
As described above, the annealed LCMO film has a large magnetoresistance effect at room temperature, and enables highly sensitive magnetic detection at room temperature.

[0053]

[Table 2]

As-deposition LCMO prepared in Table 2
The film and the as-deposited LCMO film are placed in an oxygen atmosphere.
The magnetoresistance effect characteristics of the annealed LCMO film subjected to oxygen annealing at 580 ° C. for 2 hours at 77 K, room temperature, and magnetic transition temperature (T _c ) at an applied magnetic field of 1 Tesla are summarized. In the annealed LCMO film, the magnetic transition temperature rises to approximately room temperature due to the introduction of oxygen into the film.
As shown in Table 2, in the as-deposited LCMO film,
A very large magnetoresistance effect of about -50% occurs near the magnetic transition temperature. On the other hand, in an annealed LCMO film,
The magnetic transition temperature moves to room temperature, and a large magnetoresistance effect of about -15% occurs at room temperature. As described above, in the case of the LCMO film, if the magnetic detection is performed near the magnetic transition temperature, extremely high-sensitivity magnetic detection becomes possible.

In the case where a three-layered magnetoresistive film is used as a component of the magnetoresistive element of the present invention, for example, the upper and lower magnetic films are LCMO films, and the nonmagnetic film is an oxide superconductive material YB.
An a ₂ Cu ₃ O _y film (hereinafter abbreviated as YBCO) is used. Multilayer magnetoresistive film LC which is a component of magnetoresistive element
The MO / YBCO / LCMO three-layer film was formed by an ion beam sputtering method in the same manner as the above-described method for producing the LCMO film. However, the thicknesses of the upper and lower LCMO films are both 1
The thickness of the intermediate YBCO layer (d _y ) is 5
It varied between 00 and 6000 °. LCMO film and YBC
Table 1 shows details of the conditions for forming the O film. However, YBCO
The target at the time of film production is 6 inches in diameter and 5 mm in thickness.
A sintered body composed of yttrium, barium, copper, and oxygen was used. LCMO / YBCO /
Each of the LCMO three-layer films was a c-axis oriented film. The observation of the cross-sectional SEM image shows that the LCMO / YBCO
The / LCMO3 layer film has an upper and lower magnetoresistive effect LC even when the thickness of the intermediate oxide conductive YBCO film is as thin as 500 °.
There were no pinholes between the MO films. Magnetoresistance measurement, specific resistance measurement, magnetization measurement, and the like of the three-layer film were performed in the same manner as the LCMO single-layer film. FIG. 9 shows the temperature dependence of the specific resistance of the LCMO / YBCO / LCMO three-layer film when d _y = 1200 °, together with the LCMO single-layer film. LCMO / YB
The effect of superconductivity was observed at about 30K on the specific resistance of the CO / LCMO three-layer film. In addition, the magnetoresistance effect of the LCMO / YBCO / LCMO three-layer film is not saturated with a magnetic field of 1 Tesla and is an isotropic magnetoresistance effect independent of the angle between the magnetic field direction and the current direction, like the LCMO single-layer film. Was. Dy = 5 in FIG.
LCMO / Y for 00, 1500 and 2500
The temperature dependence of the magnetoresistance ratio of the BCO / LCMO three-layer film at an applied magnetic field of 1 Tesla is shown together with the LCMO single-layer film. As shown in FIG. 10, LCMO / YBCO / LCMO
The magnetoresistive effect of the three-layer film is amplified below that of the LCMO single-layer film below 140K where the magnetization is saturated, and the intermediate YB
The amplification increases as the thickness of the CO layer decreases. FIG. 11 shows the YBC of the magnetoresistance ratio of the LCMO / YBCO / LCMO three-layer film at an applied magnetic field of 1 Tesla and a temperature of 77K.
The graph shows dependency on the thickness (d _y ) of the O layer. As shown in FIG.
The magnetoresistance effect of the LCMO / YBCO / LCMO three-layer film increases as the thickness of the middle YBCO layer decreases, and when the thickness of the middle YBCO layer increases, the steepness starts at around 2500 °. To decrease. FIG.
2, d _y = 500 °, 1500 ° at a temperature of 77K,
The magnetic field dependence of the magnetization of the LCMO / YBCO / LCMO three-layer film at 2500 ° is shown. As shown in FIG. 12, the saturation magnetic field at which the magnetization is saturated increases as the thickness of the intermediate YBCO layer decreases. These results indicate that the 2500 mm thick Y
This shows that a magnetic interaction is exerted between the two LCMO layers via the BCO layer. As described above, below the temperature at which the magnetization of LCMO is saturated, LCMO
/ YBCO / LCMO 3 layer film has a magnetoresistive effect of LCMO
Higher sensitivity magnetic detection is possible compared to a single layer film.

[0056]

[Table 3]

The as-deposition 3 prepared in Table 3
The magnetoresistance effect characteristics at 77 K, room temperature, and magnetic transition temperature (T _c ) of the layer film and the three-layer film subjected to the annealing treatment at an applied magnetic field of 1 Tesla are shown. However, the annealing is an oxygen annealing at 580 ° C. for 2 hours in an oxygen atmosphere. As shown in Table 3, the magnetoresistance change of the three-layered annealing film at room temperature is as large as -6.4%, and high-sensitivity magnetic detection at room temperature is possible.

FIG. 13 shows an embodiment in which at least the oxide magnetoresistive film of the present invention is used as a magnetic detecting element in a magnetic recording / reproducing apparatus having a recording / reproducing separation type head. The read / write separation head includes a read head using the magnetoresistive element of the present invention, an inductive write head, and a shield portion for preventing the read head from being disrupted by a leakage magnetic field. As the head, a recording head including a lower magnetic film 52, an upper magnetic film 51, and a coil 60 for applying a magnetomotive force to the substrate is formed on a substrate 40, and then a lower shield 32, an oxide magnetoresistive single-layer film (or an oxide film). A read head composed of a magnetoresistive film / oxide conductive film / oxide magnetoresistive film three-layer film) 10, an electrode 20, and an upper shield 31 is formed.

[0059]

According to the present invention, it is possible to obtain a magnetoresistive film having a high sensitivity for magnetic detection and a simple element structure.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a magnetic recording / reproducing apparatus using an oxide magnetoresistive film of the present invention.

FIG. 2 is a conceptual diagram of a reproducing portion of a magnetic recording / reproducing apparatus using the oxide magnetoresistive film of the present invention.

FIG. 3 is a conceptual diagram of a configuration of a magnetic recording / reproducing apparatus of the present invention.

FIG. 4 is a diagram showing a spin structure of a Mn oxide magnetic material LCMO.

FIG. 5 is a diagram showing temperature dependence of magnetization and specific resistance of an LCMO single layer film.

FIG. 6 is a diagram showing the magnetic field dependence of the magnetoresistance effect of an LCMO single layer film.

FIG. 7 is a diagram showing the temperature dependence of the magnetoresistance effect of the LCMO single layer film.

FIG. 8 is a diagram showing the temperature dependence of the magnetoresistance effect of the annealing LCMO single layer film.

FIG. 9 is a diagram showing the temperature dependence of the specific resistance of the LCMO / YBCO / LCMO three-layer film.

FIG. 10 is a diagram showing the temperature dependence of the magnetoresistance effect of the LCMO / YBCO / LCMO three-layer film and the LCMO single-layer film.

FIG. 11 is a diagram showing the dependence of the magnetoresistance effect of the LCMO / YBCO / LCMO three-layer film on the thickness of the YBCO layer.

FIG. 12 is a diagram showing the magnetic field dependence of the magnetization of the LCMO / YBCO / LCMO three-layer film.

FIG. 13 is a view showing an embodiment of a magnetic recording / reproducing apparatus using the oxide magnetoresistive film of the present invention.

[Explanation of symbols]

10 ... Oxide magnetoresistive film (or oxide magnetoresistive film / oxide conductive film / oxide magnetoresistive film 3 layer film), 20 ... electrode, 31 ... upper shield, 32 ... lower shield, 40 ... Substrate, 51: Upper magnetoresistive film for magnetic recording, 52: Lower magnetoresistive film for magnetic recording, 60: Coil, 71: Disk, 72: Head slider,
73 ... actuator, 74 ... signal processing system, 75 ... spindle motor, 80 ... leakage magnetic field.

Continued on the front page (72) Inventor Yoko Sugaya 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Yuzo Kozo 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Shares (56) References JP-A-61-77115 (JP, A) JP-A-4-269878 (JP, A) JP-A-61-159778 (JP, A) JP-A-6-140687 (JP, A) JP-A-4-287381 (JP, A) JP-A-3-105807 (JP, A) JP-A-5-63249 (JP, A) Yuzo Kozono et al. Conduction Proximity Effect, Japan Society of Applied Magnetics Research Group, Vol. 75, pp. 29-35 Appl. Phys. Lett. , Vol. 64, no. 22 (1994, pp. 3045-3047 Phys. Rev. Lett., Vol. 71, No. 14 (1993), pp. 2331-2333 Appl. Phys. Lett., Vol. 62, No. 7 (1993). Pp. 780-782 Appl. Phys. Lett., Vol. 63, No. 14 (1993), pp. 1990-1992 Sov. J. Temp. Phys., Vol. 16, No. 12 (1990), pp. 896-898 Physica B, Vol. 155 (1989), pp. 362-365 (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 43/08 G01R 33/09 G11B 5/39 H01F 10 / 18 H01L 43/10 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A magnetoresistive head comprising a magnetoresistive film made of any one selected from the group consisting of the following materials. Bi ₁ Mn ₁ O _y , Ba ₁ Fe ₁ O _y , Sr ₁ Co ₁ O
_y , (La, A) ₁ Co ₁ O _y (where A is Ba, Pb, Cd
(La, A) ₁ B ₁ C ₁ O _y (where A is at least one or more rare earth elements, B is at least one or more alkaline earth elements, C is Fe, Co, At least one element of Mn, Ni, Cr, Co), [(Pr, Nd), (Ba, Sr)] ₁ Mn ₁ O _y , (Bi, C
a) ₁ Mn ₁ O _y , La ₁ (M, Mn) ₁ O _y (where M is Co,
At least one element of Ni, Cu, and Cr), Gd ₁ (Co, Mn) ₁ O _y , and A ₁ (Fe, B) ₁ O _y (where A
Is at least one element of Ba, Ca and Sr, and B is M
o, Mn), Bi ₁ Cr ₁ O _y , Ca ₁ Ru ₁ O _y , A ₁ (B, C) ₁ O _y (where A is at least one of Ba, Ca, Sr, Pb) Element, B is at least one element of Ni, Mn, Cr, Fe, C is at least one element of W, Sb, Mo, U), (Sr, La) ₁ (C, D) ₁ O _y (however, C is at least one element of Co and Ni, D is at least one element of Nb, Sb and Ta, and y is 2.7 to 3.3), Fe
₂ O ₃ , YFeO ₃ , CrF ₃ , NiF ₂ 2. A first magneto-resistance effect film and a second magneto-resistance effect film made of the material according to claim 1, and between the first and second magneto-resistance effect films. And an oxide conductive film having a perovskite structure formed on the substrate. 3. The magnetoresistive head according to claim 2, wherein the oxide conductive film having a perovskite structure is formed of Y.
A magnetoresistive head comprising a material containing Si, Ba, Cu and O. 4. A magnetic recording apparatus equipped with the magnetic head according to claim 1.