Self-supporting single-crystal manganite thin films having significant out-of-plane magnetic anisotropy and magnetic domain structure and methods of making the same

Abstract

This invention discloses a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, and its preparation method. The method includes the following steps: forming a sacrificial layer on a single-crystal epitaxial substrate; growing a single-crystal manganese oxide thin film on the sacrificial layer to form a laminate; attaching a flexible polymer support layer to the surface of the single-crystal manganese oxide thin film of the laminate; immersing the laminate in an etching solution, dissolving the sacrificial layer in the etching solution to separate the single-crystal epitaxial substrate and the single-crystal manganese oxide thin film; using the flexible polymer support layer to orient the single-crystal manganese oxide thin film onto a non-magnetic substrate; removing the flexible polymer support layer by heat treatment to obtain the self-supporting single-crystal manganese oxide thin film; the crystal orientation directions of the single-crystal epitaxial substrate, the sacrificial layer, and the single-crystal manganese oxide thin film are consistent. The self-supporting single-crystal manganese oxide thin film exhibits significant vertical out-of-plane magnetic anisotropy and magnetic domain structure.

Description

Technical Field

[0001] This invention relates to the fields of thin film manufacturing technology, functional material preparation, electronic equipment, and electronic devices, specifically to a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, and its preparation method. Background Technology

[0002] In recent years, the rapid development of data storage and computing technologies has placed higher demands on new materials and devices. With in-depth research on magnetic materials and spintronics, magnetic thin films with perpendicular magnetic anisotropy (PMA), such as single-crystal perovskite manganese oxide thin films, are ideal for constructing new-generation ultra-high-density magnetic memories and nano-logic devices. Current research shows that the out-of-plane anisotropy and magnetic domain structure of single-crystal perovskite manganese oxide ferromagnetic thin films will show great application prospects in magnetic memory devices and logic devices. Therefore, magnetic anisotropy plays an important role in the development of manganese-based thin-film magnetic devices.

[0003] However, the current challenge lies in the difficulty of epitaxially growing single-crystal oxide films with vertical magnetic anisotropy on any semiconductor substrate (such as silicon). Currently, oxide films can only be deposited and grown on single-crystal substrates with specific matching structures using physical or chemical vapor deposition processes. Furthermore, the in-plane / out-of-plane magnetic anisotropy of single-crystal perovskite manganese oxide films epitaxially grown on these substrates is significantly affected by the stress of the epitaxial substrate, and may even be suppressed. Therefore, how to overcome these constraints and realize single-crystal oxide films with significant magnetic anisotropy and magnetic domain structures on any semiconductor target substrate to achieve silicon-based device integration and the application of novel magnetic storage devices has become a focus of current research. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention proposes a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, and its preparation method.

[0005] The first objective of this invention is to provide a self-supporting monocrystalline manganese oxide thin film, the thin film comprising a monocrystalline manganese oxide thin film attached to a non-magnetic substrate; The single-crystal manganese oxide thin film is a single-crystal manganese oxide La. 0.7 Ba 0.3 MnO3 is ferromagnetic in the range of 5–200 K, and its Curie temperature is T. C The K value is between 200 and 250 K, and it is paramagnetic above 280 K. The lattice constant of the single-crystal manganese oxide thin film and La 0.7 Ba0.3 The lattice constant deviation of bulk MnO3 material is less than 0.003 nm. Single-crystal manganese oxide thin films are not constrained by the lattice of non-magnetic substrates. The in-plane direction of single-crystal manganese oxide thin films is easy to magnetize, and the out-of-plane direction is difficult to magnetize. The non-magnetic substrate is a non-magnetic or paramagnetic semiconductor substrate.

[0006] Furthermore, this single-crystal manganese oxide thin film is a typical giant magnetoresistive material, exhibiting ferromagnetism at low temperatures, a relatively high Curie temperature (Tc ≈ 340 K in the bulk sample), and a large magnetoelastic coupling constant.

[0007] The non-magnetic substrate is one of a silicon substrate, a sapphire substrate, or quartz glass, preferably a silicon substrate; Furthermore, the thickness of the non-magnetic substrate is 1-2 mm; The thickness of the upper film is 60-100 nm; The second objective of this invention is to provide a method for preparing a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure. This method enables integration with any non-magnetic semiconductor substrate, such as silicon, and is compatible with semiconductor processes. It provides an ideal magnetic thin film material for the design and development of novel silicon-based magnetic devices and spintronic devices. The method includes the following steps: A sacrificial layer is formed on a single-crystal epitaxial substrate; A single-crystal manganese oxide film is grown on the sacrificial layer to form a laminate; A flexible polymer support layer is attached to the surface of the single-crystal manganese oxide film of the laminate, and then immersed in an etching solution to dissolve the sacrificial layer in the etching solution in order to separate the single-crystal epitaxial substrate and the single-crystal manganese oxide film. The monocrystalline manganese oxide film was directionally transferred onto a non-magnetic substrate using a flexible polymer support layer. The flexible polymer support layer was then removed by heat treatment to obtain a self-supporting monocrystalline manganese oxide film. The crystal orientation of the single-crystal epitaxial substrate and the sacrificial layer and the single-crystal manganese oxide thin film is consistent. The non-magnetic substrate includes a non-magnetic substrate or a paramagnetic semiconductor substrate.

[0008] Furthermore, the single-crystal epitaxial substrate is one of SrTiO3, LaAlO3, or LSAT single-crystal substrate, with the crystal plane orientation being (001). The water-soluble sacrificial layer is Sr4Al2O7, Sr3Al2O6, Ca 1.5 Sr 1.5 One type of Al2O6 thin film, with a sacrificial layer thickness of 30-50 nm; The single-crystal manganese oxide thin film is a single-crystal manganese oxide La. 0.7 Ba0.3 MnO3, wherein the thickness of the single-crystal manganese oxide film is 60-100 nm; The sacrificial layer is deposited using pulsed laser deposition. During deposition, the distance between the sacrificial layer target and the single-crystal epitaxial substrate is 4-8 cm. When growing monocrystalline manganese oxide thin films, the distance between the target material and the sacrificial layer of the monocrystalline manganese oxide thin film is 4-8 cm.

[0009] Furthermore, the flexible polymer support layer is one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), or polyimide (PI). The etching solution is deionized water.

[0010] Furthermore, the oxygen pressure used in depositing the water-soluble sacrificial layer using the pulsed laser method is 5 × 10⁻⁶. -3 Pa, deposition time 3-5 min; When depositing the upper film using the pulsed laser method, the oxygen pressure was 30 Pa and the deposition time was 5-10 min.

[0011] Furthermore, the single-crystal epitaxial substrate used in the pulsed laser method is ultrasonically cleaned in acetone, ethanol and deionized water for 10-15 minutes before deposition, dried with nitrogen gas and then placed on the heating stage of the cavity.

[0012] Furthermore, the pulse frequency used in the pulsed laser method is 5-20Hz; the laser energy density used in the pulsed laser method is 1.5-30J / cm². 2 The deposition temperature used in the pulsed laser method is 600-800℃.

[0013] Furthermore, in the heat treatment, a transfer stage is used to heat the flexible polymer support layer and the single-crystal manganese oxide film; the temperature of the heat treatment is 80-100℃; and the holding time of the heat treatment is 10-15 minutes.

[0014] The self-supporting single-crystal manganese oxide thin film provided by this invention is freed from the stress influence of the epitaxial substrate, and the internal stress field is released isotropically, exhibiting significant vertical out-of-plane magnetic anisotropy and magnetic domain structure, thus solving to a certain extent the constraint of substrate stress on the magnetic anisotropy of the thin film.

[0015] The preparation method proposed in this invention is compatible with semiconductor processes. The self-supporting manganese oxide thin film prepared can be assembled with any non-magnetic substrate such as silicon to realize the integration of silicon-based devices, providing an ideal magnetic thin film material for the design and development of novel silicon-based magnetic devices and spintronic devices.

[0016] Compared with the prior art, the beneficial effects of the present invention by adopting the above technical solution are as follows: (1) The present invention provides a self-supporting single crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, wherein the perovskite structure single crystal manganese oxide thin film serves as a functional layer, is freed from the stress influence of the epitaxial substrate, and the internal stress field is isotropically released, exhibiting significant vertical out-of-plane magnetic anisotropy and magnetic domain structure.

[0017] (2) This invention has, to a certain extent, solved the problem of the influence of substrate stress on the magnetic anisotropy of thin films. The preparation method proposed in this invention is compatible with semiconductor processes, and the self-supporting manganese oxide thin film prepared can be assembled with any non-magnetic substrate such as silicon to realize the integration of silicon-based devices, providing an ideal magnetic thin film material for the design and development of novel silicon-based magnetic devices and spintronic devices.

[0018] (3) Compared with the magnetic anisotropy and magnetic domains of epitaxial single-crystal manganese oxide films grown on single-crystal substrates, which are altered or suppressed by the modulation of substrate stress, the self-supporting single-crystal manganese oxide films prepared on any non-magnetic substrate of the present invention have significant out-of-plane magnetic anisotropy and the out-of-plane magnetic domain distribution can be controlled by an external magnetic field. The anisotropic self-supporting single-crystal manganese oxide films of the present invention can play a huge application potential in the fields of silicon-based integrated magnetic memory devices and spintronic devices. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the experimental process for a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, and its preparation method, according to the present invention. LBMO represents La. 0.7 Ba 0.3 The abbreviation for MnO3; Figure 2 The self-supporting single-crystal manganese oxide transferred to a non-magnetic sapphire Al2O3 substrate in this embodiment of the invention. XRD energy spectrum of the thin film; Figure 3 The self-supporting single-crystal manganese oxide transferred to a non-magnetic Si-based surface in this embodiment of the invention. MT curve of the thin film; Figure 4 The self-supporting single-crystal manganese oxide transferred to a non-magnetic Si-based surface in this embodiment of the invention. In-plane and out-of-plane MH curves of the thin film; Figure 5 The self-supporting single-crystal manganese oxide transferred to a non-magnetic Si-based platinum-plated surface in this embodiment of the invention. Measurement diagram of out-of-plane oriented magnetic domain distribution in thin films; Figure 6The self-supporting single-crystal manganese oxide transferred to a non-magnetic Si-based platinum-plated surface in this embodiment of the invention. The out-of-plane orientation magnetic domains of the thin film are modulated and changed under the action of an external magnetic field; Figure 7 As shown in Comparative Example 1 of this invention, a single-crystal manganese oxide epitaxially grown on an LAO substrate. In-plane and out-of-plane MH curves of the thin film, where LAO is an abbreviation for LaAlO3; Figure 8 In Comparative Example 2 of this invention, single-crystal manganese oxide epitaxially grown on an LSAT substrate In-plane and out-of-plane MH curves of the thin film, where LSAT is an abbreviation for (La,Sr)(Al,Ta)O3; Figure 9 In Comparative Example 2 of this invention, single-crystal manganese oxide epitaxially grown on an LSAT substrate High-resolution XRD diffraction pattern of thin films with asymmetric (103) reciprocal space mapping; Detailed Implementation

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0021] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] The embodiments provided by this invention relate to a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, and its preparation method. The specific operation steps are as follows: Step 1: Use An excimer laser is used to sequentially epitaxially deposit a water-soluble sacrificial layer and a single-crystal manganese oxide thin film on a single-crystal epitaxial substrate using pulsed laser deposition (PLD) to obtain a laminate.

[0023] This step utilizes a single-crystal epitaxial substrate and pulsed laser deposition (PLD) technology to ensure that the grown single-crystal manganese oxide film has a high degree of single crystallinity and a specific crystal orientation. Furthermore, PLD technology can better maintain the consistency of chemical composition between the target material and the film, ensuring the accurate chemical ratio of the single-crystal manganese oxide and thus guaranteeing magnetic properties. A water-soluble sacrificial layer is introduced between the growth substrate and the functional film to provide a chemical channel for the subsequent complete peeling of the film from the substrate, achieving self-support.

[0024] Step 2: A flexible polymer support layer is attached to the surface of the single-crystal manganese oxide film of the laminate. The laminate is then placed in an etching solution, and the sacrificial layer is removed by wet etching to separate the single-crystal manganese oxide film from the single-crystal epitaxial substrate, thereby obtaining a single-crystal manganese oxide film without an epitaxial substrate.

[0025] This step dissolves the sacrificial layer, severing the physical connection between the monocrystalline manganese oxide film and the original growth substrate. This frees the monocrystalline manganese oxide film from the original substrate, and after removing the rigid substrate, the monocrystalline manganese oxide film becomes an independent, self-supporting film on a macroscopic scale. Wet etching, compared to dry etching or mechanical stripping, can reduce stress damage to the monocrystalline manganese oxide film, maintain the integrity of the monocrystalline manganese oxide film structure, and avoid destroying the magnetic domain structure.

[0026] Step 3: The monocrystalline manganese oxide film is directionally transferred onto a non-magnetic substrate using a flexible polymer support layer. The flexible polymer support layer is then removed by heat treatment to obtain a self-supporting monocrystalline manganese oxide film.

[0027] In this step, a flexible polymer is used as a temporary carrier to provide mechanical support, ensuring that the single-crystal manganese oxide thin film does not crack or fold during the transfer from the liquid environment to the target substrate and can be transferred in a directional manner; a non-magnetic substrate is used to ensure that magnetic interference from the substrate can be eliminated; the flexible polymer support layer is removed by heat treatment to avoid residual organic matter affecting the surface properties or magnetic properties of the single-crystal manganese oxide thin film, and finally a clean, directly applicable self-supporting single-crystal manganese oxide thin film device is obtained.

[0028] In step one above: In some embodiments of the present invention: (1) Depositing a water-soluble sacrificial layer on the surface of a single-crystal epitaxial substrate: a perovskite LSAT was selected as the single-crystal epitaxial substrate, with the crystal orientation of the single-crystal epitaxial substrate being

[001] . The single-crystal epitaxial substrate was sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 10-15 minutes, dried with nitrogen, and then placed on the heating stage of the deposition chamber. Sr3Al2O6 was selected as the target material for the water-soluble sacrificial layer. The distance between the target material of the water-soluble sacrificial layer and the single-crystal epitaxial substrate was set to 4-8 cm. The pulse frequency of the KrF excimer laser was set to 5-20 Hz, and the laser energy density was controlled at 1.5-30 J / cm. 2 When depositing the water-soluble sacrificial layer using pulsed laser deposition, the deposition temperature is 600-800℃. During the epitaxial deposition of the water-soluble Sr3Al2O6 thin film, the flowing oxygen pressure is 5 × 10⁻⁶. -3 After a deposition time of 3-5 min, an LSAT substrate covered with a Sr3Al2O6 film with a thickness of 30-50 nm was obtained.

[0029] (2) A single-crystal manganese oxide film was deposited on the surface of the water-soluble sacrificial layer Sr3Al2O6 film, using single-crystal La... 0.7 Ba 0.3 Using a MnO3 target, the oxygen pressure was set to 20 Pa during deposition, and after 5-10 minutes of deposition, a La layer with a thickness of 60-100 nm was obtained. 0.7 Ba 0.3 After MnO3 film deposition, a laminate was obtained: LSAT-Sr3Al2O6 film-La 0.7 Ba 0.3 MnO3 thin film structure.

[0030] In step two above: In some embodiments of the present invention: polydimethylsiloxane (PDMS) is selected as a flexible polymer support layer, deionized water is selected as the etching solution, the PDMS support layer is attached to the surface of the single-crystal manganese oxide film of the laminate, and etched by immersion in deionized water. The etching process is carried out at room temperature and pressure. After etching for 30-60 minutes, the Sr3Al2O6 sacrificial layer dissolves, and the LSAT single-crystal substrate and La... 0.7 Ba 0.3 MnO3 thin film separation yielded a single-crystal manganese oxide thin film without an epitaxial substrate.

[0031] In step three above: In some embodiments of the present invention: using a transfer stage device, the single-crystal manganese oxide film (single-crystal La) stripped from the epitaxial substrate is transferred via polydimethylsiloxane PDMS. 0.7 Ba 0.3 MnO3 thin film) transferred to a non-magnetic semiconductor substrate: silicon wafer, 1-2 mm thick, mechanical stress applied and held for 5 min, then heated at 80-100 °C for 10 min to peel off polydimethylsiloxane (PDMS), self-supporting single-crystal La 0.7 Ba 0.3 The transfer of MnO3 thin film to the Si substrate surface is completed, i.e., self-supporting single-crystal La 0.7 Ba 0.3 The interaction between the MnO3 thin film and the Si substrate is a van der Waals force, resulting in silicon-based single-crystal La. 0.7 Ba 0.3 MnO3 film.

[0032] In addition, Si-based substrates can be replaced with non-magnetic substrates such as silicon-based semiconductors coated with metal electrode layers, sapphire substrates, or quartz glass.

[0033] Figure 1This is a schematic diagram of the experimental process for a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, and its preparation method, according to the present invention. LBMO represents La. 0.7 Ba 0.3 The abbreviation for MnO3; Figure 2 The self-supporting single-crystal manganese oxide transferred to a non-magnetic sapphire Al2O3 substrate in this embodiment of the invention. XRD energy spectrum of the thin film, from Figure 2 The XRD energy dispersive spectroscopy (EDS) shows that the self-supporting manganese oxide thin film prepared in this invention has a high-quality single-crystal structure. Furthermore, based on the diffraction angle at 2theta and the Bragg equation, the lattice constant of the self-supporting single-crystal LBMO thin film can be deduced to be 0.3927 nm, which is close to the lattice constant of the bulk material. This confirms that the internal stress field of the film is released, freeing it from the stress constraint of the epitaxial substrate. Figure 3 The self-supporting single-crystal manganese oxide transferred to a non-magnetic Si-based surface in this embodiment of the invention. The MT curves of the thin film (5K-380K temperature range) show that the self-supported LBMO film is ferromagnetic at low temperatures and has a Curie temperature of T. C The temperature is between 200 and 250 K, and approximately 230 K, at which point a ferromagnetic to paramagnetic transition occurs. Figure 4 The self-supporting single-crystal manganese oxide transferred to a non-magnetic Si-based surface in this embodiment of the invention. The in-plane and out-of-plane MH curves of the thin film (at 5K temperature), from Figure 4 As can be seen, the magnetic moment of the self-supporting single-crystal LBMO film rapidly saturates to Mr under an in-plane magnetic field, while the coercivity is relatively large at about 0.125T under an out-of-plane magnetic field, which confirms that the self-supporting LBMO film exhibits significant in-plane and out-of-plane magnetic anisotropy, with the in-plane direction being the easy magnetization direction. The present invention further describes the self-supporting single-crystal oxide transferred to a non-magnetic Si-based platinum-plated surface in the embodiments. The out-of-plane orientation magnetic domain distribution of the thin film was measured, such as... Figure 5 As shown, from Figure 5 It can be seen that at zero magnetic field, the out-of-plane orientation magnetic moment of the thin film has a certain distribution, with the in-plane-out-of-plane distribution accounting for approximately 50%-50%; from Figure 6 It can be seen that when the out-of-plane measurement magnetic field is increased to 2000 Oe, the in-plane magnetic moments of the thin film are reoriented, and the proportion of out-of-plane magnetic domains (green area) increases, confirming the self-supporting single-crystal oxide. The out-of-plane oriented magnetic domains of the thin film are effectively modulated by an external magnetic field; Comparative Examples 1 and 2: Single-crystal manganese oxide LBMO thin films were directly epitaxially grown on single-crystal substrates LAO and LSAT, respectively, and their magnetic anisotropy was investigated.

[0034] Figure 7 As a comparative example, a single-crystal LBMO thin film grown on an LAO substrate is subjected to in-plane compressive stress on the LAO substrate. It can be seen that the saturation magnetic moments of the in-plane and out-of-plane MH curves of the single-crystal LBMO thin film are similar, and only the coercivity is different. The in-plane and out-of-plane magnetic anisotropy is not significant.

[0035] Figure 8 For comparison, the in-plane and out-of-plane MH curves (5K temperature) of the epitaxially grown single-crystal LBMO film on the LSAT substrate are shown in Example 2. It can be seen that the out-of-plane structure of the epitaxial single-crystal LBMO film is complex. Figure 9 Comparative Example 2: Single-crystal manganese oxide epitaxially grown on an LSAT substrate The high-resolution XRD diffraction asymmetric (103) reciprocal space mapping pattern of the thin film shows that the lattice constant of the thin film and the substrate is the same in the in-plane

[100] direction, which confirms that the thin film is subjected to a large in-plane compressive stress on the LSAT substrate, resulting in a complex multiphase structure in the MH curve of the thin film.

[0036] Therefore, Comparative Examples 1 and 2 confirm that the macroscopic magnetic anisotropy of epitaxial single-crystal thin films can be affected by the stress of the epitaxial growth substrate, or even suppressed. The self-supporting single-crystal manganese oxide thin film of the present invention is free from the stress of the epitaxial substrate, the internal stress field is released isotropically, the in-plane-out-of-plane magnetic anisotropy is more significant, and the out-of-plane oriented magnetic domain region can be effectively controlled by the magnetic field.

[0037] Although the above embodiments have described the present invention and its implementation in detail, it should be noted that for those skilled in the art, any changes, modifications, substitutions, combinations, simplifications, etc., made to the corresponding conditions without departing from the technical principles of the present invention should be considered as equivalent substitutions, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-supporting single-crystal manganese oxide thin film with significant out-of-plane magnetic anisotropy and magnetic domain structure, comprising the following steps: A sacrificial layer is formed on a single-crystal epitaxial substrate; A single-crystal manganese oxide film is grown on the sacrificial layer to form a laminate; A flexible polymer support layer is attached to the surface of the single-crystal manganese oxide film of the laminate, and then immersed in an etching solution to dissolve the sacrificial layer in the etching solution in order to separate the single-crystal epitaxial substrate and the single-crystal manganese oxide film. The monocrystalline manganese oxide film was directionally transferred onto a non-magnetic substrate using a flexible polymer support layer. The flexible polymer support layer was then removed by heat treatment to obtain a self-supporting monocrystalline manganese oxide film. The crystal orientation of the single-crystal epitaxial substrate and the sacrificial layer and the single-crystal manganese oxide thin film is consistent. The non-magnetic substrate includes a non-magnetic substrate or a paramagnetic semiconductor substrate.

2. The preparation method according to claim 1, characterized in that, The sacrificial layer is Sr4Al2O7, Sr3Al2O6, and Ca. 1.5 Sr 1.5 One type of Al2O6 thin film; the single-crystal manganese oxide thin film is a single-crystal manganese oxide La. 0.7 Ba 0.3 MnO3; the thickness of the single-crystal manganese oxide film is 60-100nm; the single-crystal epitaxial substrate is one of SrTiO3, LaAlO3, or (La,Sr)(Al,Ta)O3 single-crystal substrate, with the crystal plane orientation in the (001) direction.

3. The preparation method according to claim 2, characterized in that, The sacrificial layer is deposited using pulsed laser deposition. During deposition, the distance between the sacrificial layer target and the single-crystal epitaxial substrate is 4-8 cm. When growing monocrystalline manganese oxide thin films, the distance between the target material and the sacrificial layer of the monocrystalline manganese oxide thin film is 4-8 cm.

4. The preparation method according to claim 1, characterized in that, The flexible polymer support layer is one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), or polyvinyl alcohol (PVA). The etching solution is deionized water.

5. The preparation method according to claim 2, characterized in that, The oxygen pressure used in the deposition of the sacrificial layer using the pulsed laser method is 5 × 10⁻⁶. -3 Pa, deposition time 3-5 min; When depositing single-crystal manganese oxide thin films using the pulsed laser method, the oxygen pressure used is 30 Pa and the deposition time is 5-10 min. The pulsed laser method uses a pulse frequency of 5-20Hz; The pulsed laser method uses a laser energy density of 1.5-30 J / cm². 2 ; The pulsed laser method uses a deposition temperature of 600-800℃.

6. The preparation method according to claim 1, characterized in that, In the heat treatment, a transfer stage is used to heat the flexible polymer support layer and the single-crystal manganese oxide film. The temperature of the heat treatment is 80-100℃; The heat treatment holding time is 10-15 minutes.

7. A self-supporting single-crystal manganese oxide thin film, characterized in that, The self-supporting monocrystalline manganese oxide film is prepared by the preparation method according to any one of claims 1 to 6, comprising a monocrystalline manganese oxide film attached to a non-magnetic substrate. The single-crystal manganese oxide thin film is a single-crystal manganese oxide La. 0.7 Ba 0.3 MnO3 is ferromagnetic in the range of 5–200 K, and its Curie temperature is T. C The K value is 200~250K, and it is paramagnetic above 280K; The lattice constant of the single-crystal manganese oxide thin film and La 0.7 Ba 0.3 The lattice constant deviation of bulk MnO3 material is less than 0.003 nm. Single-crystal manganese oxide thin films are not constrained by the lattice of non-magnetic substrates. The in-plane direction of single-crystal manganese oxide thin films is easy to magnetize, and the out-of-plane direction is difficult to magnetize. The non-magnetic substrate is a non-magnetic or paramagnetic semiconductor substrate.

8. The single-crystal manganese oxide thin film as described in claim 7, characterized in that, The non-magnetic substrate includes one of a silicon substrate, a sapphire substrate, or quartz glass.

9. The single-crystal manganese oxide thin film as described in claim 7, characterized in that, The thickness of the non-magnetic substrate is 1-2 mm; The thickness of the single-crystal manganese oxide film is 60-100 nm.

10. The application of the self-supporting single-crystal manganese oxide thin film prepared by the method of any one of claims 1 to 6, or the self-supporting single-crystal manganese oxide thin film of any one of claims 7 to 9, in the fabrication of magnetic storage devices and spintronic devices.

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