Magnetic device formed by cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy and method

Abstract

The invention discloses a preparation method of a magnetic device which is composed of a cobalt-iron-silicon / palladium multilayer film and has perpendicular magnetic anisotropy. The preparation method comprises the following specific steps: step 1, directly depositing a Ta buffer layer on a substrate by a magnetron sputtering method; step 2, alternately depositing the Co2FeSi layers and the Pd layers by using a magnetron sputtering method to form a [Co2FeSi / Pd] n magnetic multilayer film, wherein n is the number of stacking cycles; step 3, depositing a covering layer on the [Co2FeSi / Pd] n multilayer film by a magnetron sputtering method; and 4, annealing: after deposition of the Pd covering layer is finished, annealing the sample. The invention further discloses the magnetic device prepared by the method. The magnetic device has perpendicular magnetic anisotropy performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of ferromagnetic metal thin film materials, and in particular relates to a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, and also relates to a method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy. Background Art

[0002] Perpendicular magnetic anisotropy refers to the phenomenon that the magnetic moment (or magnetization direction) inside a magnetic material is preferentially arranged in a direction perpendicular to the film plane. This property makes it easier for the magnetization direction of the material to be arranged in a perpendicular direction rather than a parallel direction, which has important application value in the fields of magnetic storage devices, magnetic sensors, and spin electronics. The spin polarization rate of traditional materials with perpendicular magnetic anisotropy is usually small, which greatly limits their further application. Co2FeSi, as a material with high spin polarization rate, has attracted widespread attention from researchers. Among the existing technical means, the perpendicular magnetic anisotropy of the system is achieved by changing the preparation conditions such as thickness and annealing temperature in Pt / Co2FeSi / MgO and Pd / Co2FeSi / MgO sandwich structure films. In order to meet the needs of modern information technology for high storage density and high-performance magnetic devices and further improve the performance of spin electronics devices, it is of great significance to design and develop magnetic multilayer films with perpendicular magnetic anisotropy. Summary of the invention

[0003] The first object of the present invention is to provide a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, which magnetic device has perpendicular magnetic anisotropy energy and is helpful for developing spin electronic devices based on cobalt iron silicon / palladium multilayer films ([Co2FeSi / Pd]n multilayer films).

[0004] The second object of the present invention is to provide a method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, which can be used to prepare the above-mentioned magnetic device and provide ideas for enhancing the research on the perpendicular magnetic properties of Co2FeSi multilayer films.

[0005] The first technical solution adopted by the present invention is a method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, and the specific steps are as follows:

[0006] Step 1. Depositing a Ta buffer layer directly on the substrate by magnetron sputtering;

[0007] Step 2. Use magnetron sputtering to alternately deposit Co2FeSi layers and Pd layers to form [Co2FeSi / Pd] n Magnetic multilayer film, n is the number of stacking periods;

[0008] Step 3. Magnetron sputtering on [Co2FeSi / Pd] n depositing a capping layer on the multilayer film;

[0009] Step 4. Annealing: After the deposition of the capping layer, the sample is annealed.

[0010] The present invention is also characterized in that:

[0011] In step 1, the substrate is a Si substrate, a SiO2 substrate or a Si substrate with a pre-imprinted pattern.

[0012] The deposition of each layer of material in the magnetic device is prepared by a magnetron sputtering system, the sputtering atmosphere is argon, and the argon flow rate is 18sccm-36sccm.

[0013] The substrate rotation speed in the magnetron sputtering system is 10rpm-20rpm.

[0014] In step 2, [Co2FeSi / Pd] n The multilayer film is formed by alternating deposition of Co2FeSi layers and Pd layers. Deposition of one Co2FeSi layer and one Pd layer constitutes one cycle, and the number of stacking cycles n is 1 to 7.

[0015] In step 3, the material of the covering layer is a non-ferromagnetic heavy metal. In step 4, the annealing temperature is 250° C.-350° C., and the annealing time is 0.5 h-2 h.

[0016] The second technical solution adopted by the present invention is that a magnetic device composed of a cobalt-iron-silicon / palladium multilayer film and having perpendicular magnetic anisotropy is prepared by the above method.

[0017] The beneficial effects of the present invention are:

[0018] The method of the present invention prepared [Co2FeSi / Pd] n Multilayer films can achieve perpendicular magnetic anisotropy even if the Co2FeSi layer itself has in-plane magnetic anisotropy. The multilayer film structure enhances the perpendicular magnetic anisotropy of the system by using the multi-interface effect, which is helpful for the development of spintronic devices based on cobalt iron silicon / palladium multilayer films ([Co2FeSi / Pd]n multilayer films) and provides ideas for enhancing the perpendicular magnetic properties of Co2FeSi multilayer films, which will have great potential application value in information storage fields such as high-density perpendicular magnetic recording and magneto-optical storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy according to the present invention;

[0020] Figure 2is the in-plane and out-of-plane hysteresis loop of the magnetic device composed of the cobalt-iron-silicon / palladium multilayer film annealed at 300° C. for 1 h and having perpendicular magnetic anisotropy in Example 1;

[0021] Figure 3 The in-plane and out-of-plane hysteresis loops of the magnetic device composed of the cobalt-iron-silicon / palladium multilayer film annealed at 300° C. for 1 h and having perpendicular magnetic anisotropy in Example 2;

[0022] Figure 4 The in-plane and out-of-plane hysteresis loops of the magnetic device composed of the cobalt-iron-silicon / palladium multilayer film annealed at 300° C. for 1 h and having perpendicular magnetic anisotropy in Example 3;

[0023] Figure 5 It is the in-plane and out-of-plane hysteresis loop of the magnetic device composed of the Co-Fe-Si / Pd multilayer film annealed at 300°C for 1h and having perpendicular magnetic anisotropy in Example 4.

[0024] In the figure, 1. substrate, 2. Ta buffer layer, 3. [Co2FeSi / Pd] n Magnetic multilayer film, 4. Covering layer; 3-1. Pd layer, 3-2. Co2FeSi layer. DETAILED DESCRIPTION

[0025] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] The present invention provides a method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, wherein all film layers are grown using magnetron sputtering technology, and the specific steps are as follows:

[0027] Step 1. Depositing a Ta buffer layer 2 directly on a substrate 1 by magnetron sputtering;

[0028] In step 1, substrate 1 is a Si substrate, a SiO2 substrate or a Si substrate with a pre-printed pattern.

[0029] Step 2. Using magnetron sputtering, alternately deposit Co2FeSi layer 3-2 and Pd layer 3-1 to form [Co2FeSi / Pd] n Magnetic multilayer film 3, n is the number of stacking periods, wherein the Co2FeSi layer is formed by DC magnetron sputtering and the Pd layer is formed by RF magnetron sputtering;

[0030] In step 2, [Co2FeSi / Pd] n The multilayer film is formed by alternately depositing Co2FeSi layers and Pd layers, wherein one Co2FeSi layer 3-2 and one Pd layer 3-1 are deposited as one cycle, and the number of stacking cycles n is 1 to 7;

[0031] Step 3. Magnetron sputtering on [Co2FeSi / Pd] nA cover layer 4 is deposited on the multilayer film 3 to prevent oxidation of the sample;

[0032] In step 3, the material of the covering layer 4 is a non-ferromagnetic heavy metal, such as Ta, Pt or Pd.

[0033] Step 4. Annealing: After the deposition of the Pd capping layer 4 is completed, the sample is annealed.

[0034] In step 4, the annealing temperature is 250° C.-350° C., and the annealing time is 0.5 h-2 h.

[0035] The deposition of each layer of material in the magnetic device is prepared by a magnetron sputtering system, the sputtering atmosphere is argon, and the argon flow rate is 18sccm-36sccm.

[0036] The substrate rotation speed in the magnetron sputtering system is 10rpm-20rpm.

[0037] The present invention also provides a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, which is prepared by the above method, such as Figure 1 As shown, the magnetic device structure is arranged from top to bottom in sequence: substrate 1, Ta buffer layer 2, [Co2FeSi / Pd] n Magnetic multilayer film 3 and Pd cap layer 4.

[0038] The specifications of the instruments used in all the following examples are as follows:

[0039] Magnetron sputtering system: brand Kurt J.Lesker, model PVD 75Proline.

[0040] Vibrating sample magnetometer: brand Microsense, model VSM-EZ9.

[0041] Vacuum annealing furnace: brand: Dongfang Chenjing, model: high temperature magnetic field heating furnace.

[0042] Example 1

[0043] A method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, wherein [Co2FeSi / Pd] nIn the multilayer film 3, n=2, a Ta buffer layer 2, a [Co2FeSi / Pd]2 multilayer film 3 and a capping layer 4 are sequentially deposited on a substrate 1 by magnetron sputtering. After the deposition of the capping layer 4 is completed, the sample is annealed; wherein the thickness of the Co2FeSi layer is 0.6nm, the thickness of the Pd layer is 2nm, the number of stacking cycles is 2, and the specific structure of the sample is SiO2 substrate (thickness is 0.5mm) / Ta buffer layer (thickness is 6nm) / [Co2FeSi (thickness is 0.6nm) / Pd (thickness is 2nm)]2 / Pd (thickness is 2nm). The film thicknesses in this embodiment are all nominal film thicknesses, the deposition temperatures are all room temperature, the sputtering atmosphere is argon, the argon flow rate is 23sccm, and the substrate rotation speed of the magnetron sputtering system is 10rpm. After the deposition is completed, the sample is placed in a vacuum annealing furnace for non-in-situ annealing, the annealing temperature is 300°C, and the annealing time is 1h. The in-plane and out-of-plane hysteresis loops were measured using a vibrating sample magnetometer (VSM). Figure 2 As shown, the sample exhibits perpendicular magnetic anisotropy under 300 °C annealing, and the easy magnetization axis is perpendicular to the film surface.

[0044] Example 2

[0045] A method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, wherein [Co2FeSi / Pd] n In the multilayer film 3, n=3, and the Ta buffer layer 2, the [Co2FeSi / Pd]3 multilayer film 3 and the covering layer 4 are sequentially deposited on the substrate 1 by magnetron sputtering. After the deposition of the covering layer 4 is completed, the sample is annealed; wherein the thickness of Co2FeSi is 0.6nm, the thickness of the Pd layer is 2nm, the number of stacking cycles is 3, and the specific structure of the sample is SiO2 substrate (thickness is 0.5mm) / Ta buffer layer (thickness is 6nm) / [Co2FeSi (thickness is 0.6nm) / Pd (thickness is 2nm)]3 / Pd (thickness is 2nm). The film thicknesses in this embodiment are all nominal film thicknesses, the deposition temperatures are all room temperature, the sputtering atmosphere is argon, the argon flow rate is 23sccm, and the substrate rotation speed of the magnetron sputtering system is 10rpm. After the deposition is completed, the sample is placed in a vacuum annealing furnace for non-in-situ annealing. The annealing temperature is 300°C and the annealing time is 1h. The in-plane and out-of-plane hysteresis loops are measured using a vibrating sample magnetometer. Figure 3 As shown, the sample exhibits perpendicular magnetic anisotropy under 300 °C annealing.

[0046] Example 3

[0047] A method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, wherein [Co2FeSi / Pd] nIn the multilayer film 3, n=4, and the Ta buffer layer 2, the [Co2FeSi / Pd]4 multilayer film 3 and the covering layer 4 are sequentially deposited on the substrate 1 by magnetron sputtering. After the deposition of the covering layer 4 is completed, the sample is annealed; wherein the thickness of Co2FeSi is 0.6nm, the thickness of the Pd layer is 2nm, the number of stacking cycles is 4, and the specific structure of the sample is SiO2 substrate (thickness is 0.5mm) / Ta buffer layer (thickness is 6nm) / [Co2FeSi (thickness is 0.6nm) / Pd (thickness is 2nm)]4 / Pd (thickness is 2nm). The film thicknesses in this embodiment are all nominal film thicknesses, the deposition temperatures are all room temperature, the sputtering atmosphere is argon, the argon flow rate is 23sccm, and the substrate rotation speed of the magnetron sputtering system is 10rpm. After the deposition is completed, the sample is placed in a vacuum annealing furnace for non-in-situ annealing. The annealing temperature is 300°C and the annealing time is 1h. The in-plane and out-of-plane hysteresis loops are measured using a vibrating sample magnetometer. Figure 4 As shown, the sample exhibits good perpendicular magnetic anisotropy under 300℃ annealing.

[0048] Example 4

[0049] A method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, wherein [Co2FeSi / Pd] n In the multilayer film 3, n=5, and the Ta buffer layer 2, the [Co2FeSi / Pd]5 multilayer film 3 and the covering layer 4 are sequentially deposited on the substrate 1 by magnetron sputtering. After the deposition of the covering layer 4 is completed, the sample is annealed; wherein the thickness of Co2FeSi is 0.6nm, the thickness of the Pd layer is 2nm, the number of stacking cycles is 5, and the specific structure of the sample is SiO2 substrate (thickness is 0.5mm) / Ta buffer layer (thickness is 6nm) / [Co2FeSi (thickness is 0.6nm) / Pd (thickness is 2nm)]5 / Pd (thickness is 2nm). The film thicknesses in this embodiment are all nominal film thicknesses, the deposition temperatures are all room temperature, the sputtering atmosphere is argon, the argon flow rate is 23sccm, and the substrate rotation speed of the magnetron sputtering system is 10rpm. After the deposition is completed, the sample is placed in a vacuum annealing furnace for non-in-situ annealing. The annealing temperature is 300°C and the annealing time is 1h. The in-plane and out-of-plane hysteresis loops are measured using a vibrating sample magnetometer. Figure 5 As shown, the sample exhibits perpendicular magnetic anisotropy under 300 °C annealing.

[0050] Example 5

[0051] The difference from Example 4 is that in this embodiment [Co2FeSi / Pd] nIn multilayer film 3, n=1, the sputtering atmosphere is argon, the argon flow rate is 18 sccm, and the substrate rotation speed of the magnetron sputtering system is 20 rpm. After the deposition is completed, the sample is placed in a vacuum annealing furnace for ex-situ annealing at a temperature of 250° C. and an annealing time of 2 h.

[0052] Example 6

[0053] The difference from Example 4 is that in this embodiment [Co2FeSi / Pd] n In multilayer film 3, n=7, the sputtering atmosphere is argon, the argon flow rate is 36 sccm, and the substrate rotation speed of the magnetron sputtering system is 5 rpm. After the deposition is completed, the sample is placed in a vacuum annealing furnace for ex-situ annealing at a temperature of 350°C and an annealing time of 0.5 h.

Claims

1. A method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, characterized in that: The specific steps are as follows: Step 1. Depositing a Ta buffer layer (2) directly on the substrate (1) by magnetron sputtering; Step 2. Use magnetron sputtering to alternately deposit Co2FeSi layers (3-2) and Pd layers (3-1) to form [Co2FeSi / Pd] n Magnetic multilayer film (3), n is the number of stacking periods; Step 3. Magnetron sputtering on [Co2FeSi / Pd] n Depositing a cover layer (4) on the multilayer film (3); Step 4. Annealing: After the deposition of the cover layer (4) is completed, the sample is annealed.

2. The method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy according to claim 1, characterized in that: In step 1, the substrate (1) is a Si substrate, a SiO2 substrate or a Si substrate with a pre-printed pattern.

3. The method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy according to claim 1, characterized in that: The deposition of each layer of material in the magnetic device is prepared by a magnetron sputtering system, the sputtering atmosphere is argon, and the argon flow rate is 18sccm-36sccm.

4. The method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy according to claim 3, characterized in that: The substrate rotation speed in the magnetron sputtering system is 5rpm-20rpm.

5. The method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy according to claim 1, characterized in that: In step 2, the number of stacking cycles n is 1 to 7.

6. The method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy according to claim 1, characterized in that: In step 3, the material of the covering layer (4) is a non-ferromagnetic heavy metal.

7. The method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy according to claim 1, characterized in that: In step 4, the annealing temperature is 250° C.-350° C., and the annealing time is 0.5 h-2 h.

8. A magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, characterized in that: The method is prepared by any one of claims 1 to 7.

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