CN107523796B - A kind of preparation method of rare earth-transition alloy composite material with spacer layer - Google Patents

Abstract

The present invention discloses a kind of preparation method of rare earth-transition alloy composite materials with wall, it fits rare earth patch and ferrocobalt target to form combined tessera target, first use magnetron sputtering combined tessera target or ternary alloy three-partalloy target, the first layer rare earth-transition alloy firm (laminated magnetic film I) of 20~50nm thickness is grown on substrate, then the metal spacing layer or oxide spacers (wall) of 0.5~2.5nm thickness are sputtered, finally continue to sputter combined tessera target or ternary alloy three-partalloy target, the second layer rare earth-transition alloy firm (laminated magnetic film II) of 7~15nm thickness is grown on wall, what is obtained is a kind of composite material that the same Ferrimagnetic rare earth-transition alloy (TbFeCo or DyFeCo) with wall is constituted.The composite property that the preparation method is prepared is stablized, and the structure of the composite material and vertical magnetoelectronic devices are completely compatible, can be used as the novel magnetoelectronic devices material of one kind in vertical spin valve or magnetic tunnel device.

Description

A kind of preparation method of rare earth-transition alloy composite material with spacer layer

technical field

The invention belongs to the field of magnetic spintronics and magnetic recording technical materials, relates to a preparation method of a composite thin film material for a perpendicular magnetic spintronic device, and in particular relates to a rare earth-transition alloy composite material with a spacer layer. Preparation.

Background technique

In recent years, magnetoelectric devices such as vertical spin valves and magnetic tunnel junctions have become the research direction in this field due to their advantages of high density and better thermal stability than in-plane devices. Among them, the magnetic memory based on the perpendicular magnetic tunnel junction is considered as one of the representative technologies of the next-generation high-density non-volatile memory. The basic functional layers such as the free layer and the reference layer in the vertical magnetic tunnel junction are required to be materials with a film plane that is perpendicular to the easy axis. Therefore, the search for vertical easy-axis thin films and their simple growth methods has become the key to fabricating high-density magnetoelectric devices.

Traditional magneto-optical recording rare earth-transition alloy thin films such as TbFeCo and DyFeCo alloy materials are widely used in the field of high-density magnetoelectric devices due to their large perpendicular magnetic anisotropy and high thermal stability. The magnetic moments of the rare earth element (Tb or Dy) and the transition element (FeCo) sublattice in this ferrimagnetic alloy thin film material are antiparallel alignment, which leads to the possible existence of a specific compensation point composition in this type of material, corresponding to this The coercivity of the compensation point composition alloy film is infinite. The composition of the rare earth-transition alloy thin film with the easy axis perpendicular to the film surface is generally located in a small composition area near the compensation point composition. When the magnetic moment of the rare earth element sublattice in the alloy film material is greater than that of the transition element sublattice at room temperature, the alloy film is a rare earth rich phase, otherwise it is a transition rich phase. Perpendicular magnetoelectric devices require rare-earth-transition alloy films with widely different vertical coercive forces to meet the requirements of the free layer (small coercivity, and the magnetization direction easily follows the direction of the external field) and the pinned layer (large coercivity) in the device. , the magnetization direction is not easy to change with the direction of the external field) and other requirements of different functional layers. Finding a preparation method of rare earth-transition alloy thin film materials with large difference vertical reversal field is of great significance in the field of current high-density magnetic spintronic devices, especially in the field of new low-power information memory such as direct current-induced magnetization reversal. Potentially huge economic benefits.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of a rare earth-transition alloy composite material with a spacer layer, the preparation process is simple, the performance of the prepared composite material is stable, the structure of the composite material is completely compatible with the perpendicular magnetoelectric device, and can be used as a A new type of magnetoelectronic device material is used in vertical spin valve or magnetic tunnel junction devices.

In order to achieve the above-mentioned purpose, the solution of the present invention is:

A preparation method of a rare earth-transition alloy composite material with a spacer layer, comprising the following steps:

(1) A composite mosaic target or a ternary alloy target composed of a rare earth patch and an iron-cobalt alloy target is used as the target for magnetron sputtering, and is installed and fixed on the sputtering target seat of the magnetron sputtering chamber. The sheet is a Tb patch or a Dy patch, the ternary alloy target is a TbFeCo alloy target or a DyFeCo alloy target, the number of rare earth patches in the composite mosaic target and the position fixed on the sputtering target seat or the The rare earth content in the ternary alloy target is such that the rare earth element composition in the prepared rare earth-transition alloy composite material is 25-27.5% (rare earth rich);

(2) the substrate after cleaning and drying is arranged and fixed on the substrate stage of the magnetron sputtering chamber, and the target-to-base distance is adjusted to be 4-8 cm;

(3) The sputtering vacuum chamber is evacuated to a degree of vacuum below 1×10 ^-5 Pa, and argon with a purity of ≥99.99% is introduced as the working gas, and the intake flow of argon is controlled within the range of 30-100sccm;

(4) Pre-sputtering the target material for 10-30min under the condition of sputtering working pressure of 0.2-1.0Pa;

(5) Adjust the substrate table to rotate 5-15 times per minute, open the baffle plate between the substrate table and the sputtering target base, and sputter the target material with a sputtering power density of 1.5-6.5 W/cm ² , The sputtering rate is 0.1-0.3 nm/s, and the sputtering time is controlled to obtain a rare earth-transition alloy film with a thickness of 20-50 nm on the substrate to form a substrate with a first layer of rare-earth-transition alloy film;

(6) Then a spacer layer is sputtered on the substrate with the first layer of rare earth-transition alloy thin film, and the sputtering time is controlled so that the thickness of the grown spacer layer is 0.5-2.5 nm, forming a spacer layer with a thickness of 0.5-2.5 nm. The first layer of rare earth-transition alloy thin film substrate, the spacer layer is a metal spacer layer or an oxide spacer layer;

(7) Finally, continue sputtering the target on the substrate with the spacer layer and the first rare earth-transition alloy thin film, and control the sputtering time so that the second layer of rare earth-transition grows on the spacer layer. The thickness of the alloy thin film is 7-15 nm, and the rare earth-transition alloy composite material with spacer layer is obtained.

In step (1), the rare earth patch is an isosceles triangle with a purity of ≥99.9%, the purity of the iron-cobalt alloy target is greater than or equal to 99.9%, and each piece of the rare earth patch is made of the iron-cobalt alloy. The center of the alloy target is attached to the iron-cobalt alloy target to form the composite mosaic target for sputtering.

In step (2), the substrate is a single crystal Si substrate or a typical commercial single crystal Si substrate with a thermally oxidized layer.

In step (4), before pre-sputtering the target, sputter a metal buffer layer or an oxide buffer layer on the substrate, and control the sputtering time so that the thickness of the metal buffer layer or the oxide buffer layer is controlled. is 0.5-2.5nm, the metal buffer layer is Ta buffer layer, Ru buffer layer, Cu buffer layer, Pd buffer layer or Pt buffer layer, and the oxide buffer layer is SiO ₂ buffer layer, MgO buffer layer or Al ₂ O ₃ buffer layer.

In step (6), the metal spacer layer is Ta spacer layer, Ru spacer layer, Cu spacer layer, Pd spacer layer or Pt spacer layer, and the oxide spacer layer is SiO ₂ spacer layer, MgO spacer layer or Al ₂ O ₃ spacer layer.

In step (6), the metal spacer layer is sputtered on the substrate with the first layer of rare earth-transition alloy thin film by direct current or radio frequency sputtering, and on the substrate with the first layer of rare earth-transition alloy thin film The oxide spacer layer is sputtered by radio frequency.

In step (7), a protective layer is sputtered by direct current or radio frequency on the obtained rare earth-transition alloy composite material to prevent oxidation, and the sputtering time is controlled so that the thickness of the protective layer is 2-20 nm. The layers are Ta protective layers, Ru protective layers, Cu protective layers, Pd protective layers or Pt protective layers.

In the field of magnetic recording technology materials, the magnetic multilayer film structure is widely used in magnetoelectric devices such as spin valves and magnetic tunnel junctions. Parallel or anti-parallel arrangement, and can maintain a stable magnetic state within a certain size of the external field range.

After the above technical solution is adopted, the present invention provides a method for preparing a rare earth-transition alloy composite material with a spacer layer, and the prepared composite structure material is a kind of ferrimagnetic rare earth-transition alloy with a spacer layer. It consists of magnetic thin film layer I/spacer layer/magnetic thin film layer II. Adjacent to the spacer layer are two magnetic thin film layers of different thicknesses, which need to be prepared from the same ferrimagnetic rare earth-transition alloy material (TbFeCo or DyFeCo). By fixing the number and position of rare earth element patches in the target, Or use a ternary alloy target with a fixed proportion of composition to achieve. The magnetic moment directions of the two magnetic thin film layers with different thicknesses adjacent to the spacer layer can be aligned in parallel or anti-parallel, and this stable state can be maintained within a certain size of the external field range. Different rich phases can be realized by adjusting the thickness of the two magnetic thin film layers in the composite material, and the interface domain wall generated by the interlayer exchange coupling can enlarge the change difference of the magnetization reversal field of the two magnetic thin film layers, and has a large differential magnetization reversal field. The rare earth-transition alloy composites can be directly used in vertical spin valve or magnetic tunnel junction devices.

The invention provides a preparation method of a rare earth-transition alloy composite material with a spacer layer, which has the characteristics of simple preparation method, good repeatability and low cost, the prepared composite material has stable performance, and the structure of the composite material is similar to that of a perpendicular magnetoelectric device. It is fully compatible and can be used as a new type of magnetoelectronic device material in vertical spin valve or magnetic tunnel junction devices.

Description of drawings

Figure 1 shows the main anomalous Hall curve and the small anomalous Hall curve of the TbFeCo(20nm)/Pd(2nm)/TbFeCo(10nm) composite material;

Fig. 2 is the abnormal Hall curve of TbFeCo(20nm)/Pd(1nm)/TbFeCo(7.5nm) composite material.

Detailed ways

In order to further explain the technical solutions of the present invention, the present invention will be described in detail below through specific embodiments.

Example 1

1. Preparation of composite materials

A preparation method of a rare earth-transition alloy composite material with a spacer layer, comprising the following steps:

(1) Four isosceles triangle high-purity (99.95% pure) Tb patches are attached to a high-purity (99.9% pure) iron-cobalt alloy target with a radius of 1 inch to form a sputtering target. Composite mosaic target, each Tb patch is distributed on the iron-cobalt alloy target with the center of the iron-cobalt alloy target as the center point, the top angle of the Tb patch is 28°, the waist length of the Tb patch is 2cm, and the thickness is 2mm;

(2) The composite mosaic target is used as the target material of magnetron sputtering, and is installed and fixed on the sputtering target seat of the magnetron sputtering chamber;

(3) The single-crystal Si substrate is ultrasonically cleaned with acetone, alcohol, and isopropanol in turn, and then dried. The dried single-crystal Si substrate is placed and fixed on the substrate stage of the magnetron sputtering chamber, and adjusted The target base distance is 6.5cm;

(4) evacuate the sputtering vacuum chamber to reach a vacuum degree of 1 × 10 ^-5 Pa, feed high-purity argon (purity of 99.999%) as the working gas, and control the intake flow of argon at 60sccm;

(5) Adjust the closing degree of the gate valve to stabilize and maintain the sputtering working pressure at 0.6Pa. First, the single-crystal Si substrate was RF-sputtered with a 1nm-thick MgO buffer layer at a sputtering power density of 1.48W/cm ² . , the sputtering rate was 0.022 nm/s, and the sputtering time was 45 s to obtain a single-crystal Si substrate with a MgO buffer layer, and then pre-sputter the composite mosaic target for 20 min;

(6) Adjust the substrate table to rotate 10 times per minute, open the baffle plate between the substrate table and the sputtering target base, and sputter the composite mosaic target with a sputtering power density of 5.9W/ ^cm2 , and the sputtering rate is 0.167 nm/s, sputtering time is 120s, a 20nm thick rare earth-transition alloy film is obtained on a single crystal Si substrate, and a single crystal Si substrate with a first layer of rare earth-transition alloy film is formed;

(7) Then, the Pd spacer layer was DC sputtered on the single crystal Si substrate with the first rare earth-transition alloy thin film, the sputtering rate was 0.125 nm/s, and the sputtering time was 16 s, so that the growth of the Pd spacer layer was With a thickness of 2 nm, a single crystal Si substrate with a spacer layer and a first rare earth-transition alloy thin film is formed;

(8) Finally, the composite mosaic target was sputtered on the single crystal Si substrate with the spacer layer and the first rare earth-transition alloy thin film. The thickness of the second rare earth-transition alloy thin film grown on it is 10 nm, and a rare earth-transition alloy composite material with a spacer layer is obtained, which is denoted as TbFeCo(20nm)/Pd(2nm)/TbFeCo(10nm) composite material, and its rare earth element Composition was -26%.

2. Performance test

The magnetic properties of the TbFeCo(20nm)/Pd(2nm)/TbFeCo(10nm) composite material are shown in Figure 1. The results show that the magnetic properties of the TbFeCo magnetic thin film layers with a thickness of 10nm and a thickness of 20nm prepared by sputtering are respectively manifested as transition-rich and rare-earth-rich phases with perpendicular magnetization reversal fields of 8.5 kOe and 2.8 kOe, respectively, with a difference of 5.7 kOe, where the main The high-level plateau in the anomalous Hall curve is also a stable magnetic state.

Therefore, by adjusting the thickness of the two magnetic thin film layers in the composite material to achieve different rich phases, the magnetic moment directions of the two magnetic thin film layers with different thicknesses can be arranged in parallel or anti-parallel (corresponding to 4 in the main anomalous Hall loop). A plateau magnetic state), the interface domain wall generated by the interlayer exchange coupling can enlarge the change difference of the magnetization reversal field of the two magnetic thin film layers, and can maintain this stable magnetic state within a certain size of the external field.

Embodiment 2

1. Preparation of composite materials

A preparation method of a rare earth-transition alloy composite material with a spacer layer, comprising the following steps:

(1) Four isosceles triangle high-purity (99.95% pure) Tb patches are attached to a high-purity (99.9% pure) iron-cobalt alloy target with a radius of 1 inch to form a sputtering target. Composite mosaic target, each Tb patch is distributed on the iron-cobalt alloy target with the center of the iron-cobalt alloy target as the center point, the top angle of the Tb patch is 28°, the waist length of the Tb patch is 2cm, and the thickness is 2mm;

(2) The composite mosaic target is used as the target material of magnetron sputtering, and is installed and fixed on the sputtering target seat of the magnetron sputtering chamber;

(3) A typical commercial single-crystal Si substrate with a 300 nm thermally oxidized _SiO2 layer was ultrasonically cleaned with acetone, alcohol, and isopropanol in turn, and then dried, and the dried single-crystal Si substrate was placed and fixed on a magnetron On the substrate stage of the sputtering chamber, adjust the target-to-base distance to 6.5cm;

(4) evacuate the sputtering vacuum chamber to reach a vacuum degree of 1 × 10 ^-5 Pa, feed high-purity argon (purity of 99.999%) as the working gas, and control the intake flow of argon at 60sccm;

(5) Adjust the closing degree of the gate valve to stabilize and maintain the sputtering working pressure at 0.6Pa, and pre-sputter the composite mosaic target for 20min;

(6) Adjust the substrate table to rotate 10 times per minute, open the baffle plate between the substrate table and the sputtering target base, and sputter the composite mosaic target with a sputtering power density of 5.9W/ ^cm2 , and the sputtering rate is 0.167 nm/s, sputtering time is 120s, a 20nm thick rare earth-transition alloy film is obtained on a single crystal Si substrate, and a single crystal Si substrate with a first layer of rare earth-transition alloy film is formed;

(7) Then, the Pd spacer layer was RF sputtered on the single crystal Si substrate with the first rare earth-transition alloy thin film, the sputtering rate was 0.125 nm/s, and the sputtering time was 8 s, so that the growth of the Pd spacer layer was With a thickness of 1 nm, a single crystal Si substrate with a spacer layer and a first rare earth-transition alloy thin film is formed;

(8) Finally, the composite mosaic target was sputtered on the single crystal Si substrate with the spacer layer and the first rare earth-transition alloy thin film. The sputtering rate was 0.167nm/s and the sputtering time was 45s, so that the spacer layer was The thickness of the second rare earth-transition alloy thin film grown on it is 7.5 nm, and a rare earth-transition alloy composite material with a spacer layer is obtained, which is denoted as TbFeCo(20nm)/Pd(1nm)/TbFeCo(7.5nm) composite material, which is The rare earth element composition was -26%.

2. Performance test

The magnetic properties of the TbFeCo(20nm)/Pd(1nm)/TbFeCo(7.5nm) composite material are shown in Figure 2. The results show that the magnetic properties of the TbFeCo magnetic thin film layers with a thickness of 7.5nm and a thickness of 20nm prepared by sputtering They are characterized by transition-rich and rare-earth-rich phases, respectively, and their perpendicular magnetization reversal fields are 7.6kOe and 1.5kOe, respectively, with a difference of 6.1kOe.

Therefore, by adjusting the thickness of the two magnetic thin film layers in the composite material to achieve different rich phases, the magnetic moment directions of the two magnetic thin film layers with different thicknesses can be arranged in parallel or anti-parallel (corresponding to the four anomalous Hall loops) Platform magnetic state), the interface domain wall generated by the interlayer exchange coupling can enlarge the change difference of the magnetization reversal field of the two magnetic thin film layers.

Embodiment 3

A preparation method of a rare earth-transition alloy composite material with a spacer layer, comprising the following steps:

(1) Four isosceles triangle high-purity (99.95% pure) Tb patches are attached to a high-purity (99.9% pure) iron-cobalt alloy target with a radius of 1 inch to form a sputtering target. Composite mosaic target, each Tb patch is distributed on the iron-cobalt alloy target with the center of the iron-cobalt alloy target as the center point, the top angle of the Tb patch is 28°, the waist length of the Tb patch is 2cm, and the thickness is 2mm;

(2) The composite mosaic target is used as the target material of magnetron sputtering, and is installed and fixed on the sputtering target seat of the magnetron sputtering chamber;

(3) The single-crystal Si substrate is ultrasonically cleaned with acetone, alcohol, and isopropanol in turn, and then dried. The dried single-crystal Si substrate is placed and fixed on the substrate stage of the magnetron sputtering chamber, and adjusted The target base distance is 6.5cm;

(4) evacuate the sputtering vacuum chamber to reach a vacuum degree of 1 × 10 ^-5 Pa, feed high-purity argon (purity of 99.999%) as the working gas, and control the intake flow of argon at 60sccm;

(5) Adjust the closing degree of the gate valve to stabilize the sputtering working pressure and maintain it at 0.6Pa. First, DC sputter a 2nm thick Ta buffer layer on the single crystal Si substrate with a sputtering power density of 0.86W/ ^cm2 . , the sputtering rate is 0.1 nm/s, and the sputtering time is 20 s to obtain a single-crystal Si substrate with a Ta buffer layer, and then pre-sputter the composite mosaic target for 20 min;

(6) Adjust the substrate table to rotate 10 times per minute, open the baffle plate between the substrate table and the sputtering target base, and sputter the composite mosaic target with a sputtering power density of 5.9W/ ^cm2 , and the sputtering rate is 0.167 nm/s, sputtering time is 120s, a 20nm thick rare earth-transition alloy film is obtained on a single crystal Si substrate, and a single crystal Si substrate with a first layer of rare earth-transition alloy film is formed;

(7) Then, the Pd spacer layer was DC sputtered on the single crystal Si substrate with the first rare earth-transition alloy thin film, the sputtering rate was 0.125 nm/s, and the sputtering time was 8 s, so that the growth of the Pd spacer layer was With a thickness of 1 nm, a single crystal Si substrate with a spacer layer and a first rare earth-transition alloy thin film is formed;

(8) Finally, the composite mosaic target was sputtered on the single crystal Si substrate with the spacer layer and the first rare earth-transition alloy thin film. The thickness of the second rare earth-transition alloy thin film grown on the top is 10 nm, and a rare earth-transition alloy composite material with a spacer layer is obtained;

(9) On the obtained rare earth-transition alloy composite material, a Ta protective layer with a thickness of 2 nm was DC sputtered at a sputtering power density of 0.86 W/cm ² , the sputtering rate was 0.1 nm/s, and the sputtering time was 20 s. To prevent oxidation, the obtained rare earth-transition alloy composite material is denoted as TbFeCo(20nm)/Pd(1nm)/TbFeCo(10nm) composite material, and its rare earth element content is ~26%.

The rare earth patch, the iron-cobalt alloy target and the single-crystal Si substrate in the above embodiments are all available in the market, and only need to be purchased according to the purity requirements.

The above-mentioned embodiments do not limit the product form and style of the present invention, and any appropriate changes or modifications made by those of ordinary skill in the art should be regarded as not departing from the scope of the present invention.

Claims (7)

1. a preparation method of the rare earth-transition alloy composite material with spacer layer, is characterized in that: comprise the following steps: (1) A composite mosaic target or a ternary alloy target composed of a rare earth patch and an iron-cobalt alloy target is used as the target for magnetron sputtering, and is installed and fixed on the sputtering target seat of the magnetron sputtering chamber. The sheet is a Tb patch or a Dy patch, the ternary alloy target is a TbFeCo alloy target or a DyFeCo alloy target, the number of rare earth patches in the composite mosaic target and the position fixed on the sputtering target seat or the The rare earth content in the ternary alloy target is such that the rare earth element composition in the prepared rare earth-transition alloy composite material is 25-27.5%; (2) the substrate after cleaning and drying is arranged and fixed on the substrate stage of the magnetron sputtering chamber, and the target-to-base distance is adjusted to be 4-8 cm; (3) The sputtering vacuum chamber is evacuated to a degree of vacuum below 1×10 ^-5 Pa, and argon with a purity of ≥99.99% is introduced as the working gas, and the intake flow of argon is controlled within the range of 30-100sccm; (4) Pre-sputtering the target material for 10-30min under the condition of sputtering working pressure of 0.2-1.0Pa; (5) Adjust the substrate table to rotate 5-15 times per minute, open the baffle plate between the substrate table and the sputtering target base, and sputter the target material with a sputtering power density of 1.5-6.5 W/cm ² , The sputtering rate is 0.1-0.3 nm/s, and the sputtering time is controlled to obtain a rare earth-transition alloy film with a thickness of 20-50 nm on the substrate to form a substrate with a first layer of rare-earth-transition alloy film; (6) Then a spacer layer is sputtered on the substrate with the first layer of rare earth-transition alloy thin film, and the sputtering time is controlled so that the thickness of the grown spacer layer is 0.5-2.5 nm, forming a spacer layer with a thickness of 0.5-2.5 nm. The first layer of rare earth-transition alloy thin film substrate, the spacer layer is a metal spacer layer or an oxide spacer layer; (7) Finally, continue sputtering the target on the substrate with the spacer layer and the first rare earth-transition alloy thin film, and control the sputtering time so that the second layer of rare earth-transition grows on the spacer layer. The thickness of the alloy thin film is 7-15 nm, and the rare earth-transition alloy composite material with spacer layer is obtained. 2. The preparation method of a rare earth-transition alloy composite material with a spacer layer according to claim 1, wherein in step (1), the rare earth patch is an isosceles triangle with a purity of ≥99.9% The rare earth patch, the purity of the iron-cobalt alloy target is ≥99.9%, and each piece of the rare earth patch is attached to the iron-cobalt alloy target with the center of the iron-cobalt alloy target as the center point to form a sputtering target. of the composite mosaic target. 3 . The method for preparing a rare earth-transition alloy composite material with a spacer layer according to claim 1 , wherein in step (2), the substrate is a single crystal Si substrate or a typical commercial thermal belt. 4 . Oxide layer single crystal Si substrate. 4 . The method for preparing a rare earth-transition alloy composite material with a spacer layer according to claim 1 , wherein in step (4), before pre-sputtering the target material, On-chip sputtering metal buffer layer or oxide buffer layer, the metal buffer layer is Ta buffer layer, Ru buffer layer, Cu buffer layer, Pd buffer layer or Pt buffer layer, the oxide buffer layer is SiO ₂ buffer layer, MgO buffer layer or Al ₂ O ₃ buffer layer. 5 . The method for preparing a rare earth-transition alloy composite material with a spacer layer according to claim 1 , wherein in step (6), the metal spacer layer is a Ta spacer layer, a Ru spacer layer, a Cu spacer A spacer layer, a Pd spacer layer or a Pt spacer layer, the oxide spacer layer is a SiO ₂ spacer layer, a MgO spacer layer or an Al ₂ O ₃ spacer layer. 6 . The method for preparing a rare earth-transition alloy composite material with a spacer layer according to claim 1 , wherein in step (6), in the base with the first layer of rare earth-transition alloy thin film. 7 . The metal spacer layer is sputtered by direct current or radio frequency on the chip, and the oxide spacer layer is sputtered by radio frequency on the substrate with the first rare earth-transition alloy thin film. 7 . The method for preparing a rare earth-transition alloy composite material with a spacer layer according to claim 1 , wherein: in step (7), on the obtained rare earth-transition alloy composite material, direct current or RF sputtering protective layer to prevent oxidation, control the sputtering time so that the thickness of the protective layer is 2-20nm, the protective layer is Ta protective layer, Ru protective layer, Cu protective layer, Pd protective layer or Pt protective layer .