Magnetic device and method composed of cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy

Abstract

The present invention discloses a method for preparing a magnetic device composed of a cobalt iron silicon / palladium multilayer film and having perpendicular magnetic anisotropy, the specific steps of which are as follows: step 1. depositing a Ta buffer layer directly on a substrate by magnetron sputtering; step 2. alternately depositing Co2FeSi layers and Pd layers by magnetron sputtering to form a [Co2FeSi / Pd] n Magnetic multilayer film, n is the number of stacking periods; Step 3. Magnetron sputtering method on [Co2FeSi / Pd] n Depositing a capping layer on the multilayer film; Step 4: Annealing: After the Pd capping layer is deposited, the sample is annealed. Also disclosed is a magnetic device prepared by the above method, which has perpendicular magnetic anisotropy.

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 in which the magnetic moments (or magnetization directions) within a magnetic material preferentially align perpendicular to the film plane. This property makes the material's magnetization more likely to align perpendicularly rather than parallel to the film plane, which has important applications in magnetic memory devices, magnetic sensors, and spintronics. Conventional materials exhibiting perpendicular magnetic anisotropy typically have low spin polarizations, significantly limiting their further applications. Co2FeSi, a material with high spin polarization, has attracted widespread attention from researchers. Existing techniques have achieved perpendicular magnetic anisotropy in Pt / Co2FeSi / MgO and Pd / Co2FeSi / MgO sandwich films by varying thickness and annealing temperature. To meet the demands of modern information technology for high-density, high-performance magnetic devices and further improve the performance of spintronics devices, the design and development of magnetic multilayer films exhibiting perpendicular magnetic anisotropy is of great significance. 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, wherein the magnetic device has perpendicular magnetic anisotropy energy and contributes to the development of spintronic 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, the specific steps of which 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 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 capping layer deposition is completed, 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-printed 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 covering layer is made of 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 when the Co2FeSi layer itself exhibits in-plane magnetic anisotropy. The multilayer film structure enhances the perpendicular magnetic anisotropy of the system through multi-interface effects, facilitating the development of spintronic devices based on cobalt iron silicon / palladium multilayers ([Co2FeSi / Pd]n multilayers). This provides insights into enhancing the perpendicular magnetic properties of Co2FeSi multilayers, which has significant potential applications in information storage fields such as high-density perpendicular magnetic recording and magneto-optical storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure 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 2The 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 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 These are the in-plane and out-of-plane hysteresis loops of the magnetic device composed of the Co-Fe-Si / Pd multilayer film annealed at 300° C. for 1 h 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 will be 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. All film layers are grown using magnetron sputtering technology. The specific steps are as follows:

[0027] Step 1. Depositing a Ta buffer layer 2 directly on the 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: Co2FeSi layer 3-2 and Pd layer 3-1 are alternately deposited by magnetron sputtering to form [Co2FeSi / Pd] n Magnetic multilayer film 3, where n is the number of stacking periods, where the Co2FeSi layer is deposited using DC magnetron sputtering and the Pd layer is deposited using RF magnetron sputtering;

[0030] In step 2, [Co2FeSi / Pd] n The multilayer film is formed by alternating deposition of Co2FeSi layers and Pd layers, wherein one Co2FeSi layer 3-2 and one Pd layer 3-1 constitute one cycle, and the number of stacking cycles n ranges from 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 the following order: 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: Oriental 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 multilayer film 3, n = 2. Magnetron sputtering was used to sequentially deposit a Ta buffer layer 2, a [Co2FeSi / Pd]2 multilayer film 3, and a capping layer 4 on substrate 1. After deposition of capping layer 4, the sample was annealed. The Co2FeSi layer had a thickness of 0.6 nm, the Pd layer had a thickness of 2 nm, and the number of stacking periods was 2. The sample's specific structure was SiO2 substrate (0.5 mm thick) / Ta buffer layer (6 nm thick) / [Co2FeSi (0.6 nm thick) / Pd (2 nm thick)]2 / Pd (2 nm thick). The film thicknesses in this example were nominal, the deposition temperature was room temperature, the sputtering atmosphere was argon, the argon flow rate was 23 sccm, and the magnetron sputtering system substrate rotation speed was 10 rpm. After deposition, the sample was placed in a vacuum annealing furnace for ex-situ annealing at 300°C for 1 h. The in-plane and out-of-plane hysteresis loops were measured using a vibrating sample magnetometer (VSM). Figure 2 As shown in Figure 3, 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 after annealing at 300 °C.

[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 in Figure 3, the sample exhibits good perpendicular magnetic anisotropy after annealing at 300 °C.

[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 after annealing at 300 °C.

[0050] Example 5

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

[0052] Example 6

[0053] The difference from Example 4 is that in this embodiment [Co2FeSi / Pd] n In Multilayer 3, n = 7, the sputtering atmosphere was argon with a flow rate of 36 sccm, and the substrate rotation speed of the magnetron sputtering system was 5 rpm. After deposition, the sample was placed in a vacuum annealing furnace for ex situ annealing at 350°C for 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), the sample is annealed; 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; The substrate rotation speed in the magnetron sputtering system is 5rpm-20rpm; In step 2, the number of stacking cycles n is 1 to 7; In step 4, the annealing temperature is 250° C.-350° C., and the annealing time is 0.5 h-2 h.

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 CoFeSi / Pd 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.

4. A magnetic device comprising 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 3.

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