CN111647942B - Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof - Google Patents

Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof Download PDF

Info

Publication number
CN111647942B
CN111647942B CN202010455831.3A CN202010455831A CN111647942B CN 111647942 B CN111647942 B CN 111647942B CN 202010455831 A CN202010455831 A CN 202010455831A CN 111647942 B CN111647942 B CN 111647942B
Authority
CN
China
Prior art keywords
ferromagnetic
heterogeneous
graphene
layer
ferromagnetic layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010455831.3A
Other languages
Chinese (zh)
Other versions
CN111647942A (en
Inventor
潘孟春
彭俊平
胡悦国
李裴森
邱伟成
胡佳飞
陈棣湘
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National University of Defense Technology
Original Assignee
National University of Defense Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by National University of Defense Technology filed Critical National University of Defense Technology
Priority to CN202010455831.3A priority Critical patent/CN111647942B/en
Publication of CN111647942A publication Critical patent/CN111647942A/en
Application granted granted Critical
Publication of CN111647942B publication Critical patent/CN111647942B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/14—Metallic material, boron or silicon
    • C23C14/18—Metallic material, boron or silicon on other inorganic substrates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/24—Vacuum evaporation
    • C23C14/28—Vacuum evaporation by wave energy or particle radiation
    • C23C14/30—Vacuum evaporation by wave energy or particle radiation by electron bombardment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/58—After-treatment
    • C23C14/5806—Thermal treatment
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
    • C30B23/02—Epitaxial-layer growth
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C30B25/18—Epitaxial-layer growth characterised by the substrate
    • C30B25/186—Epitaxial-layer growth characterised by the substrate being specially pre-treated by, e.g. chemical or physical means
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
    • C30B33/02—Heat treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/80—Constructional details
    • H10N50/85—Magnetic active materials

Abstract

The invention discloses a ferromagnetic/graphene/ferromagnetic heteroepitaxial film which comprises a graphene layer, and a second heterogeneous ferromagnetic layer and a first heterogeneous ferromagnetic layer which are respectively positioned on the upper surface and the lower surface of the graphene layer, wherein the graphene layer is obtained by direct epitaxial growth on the first heterogeneous ferromagnetic layer, and the second heterogeneous ferromagnetic layer is obtained by epitaxial growth on the graphene layer. The invention also discloses a preparation method of the film, and the film has the advantage of interface lattice epitaxial property.

Description

Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof
Technical Field
The invention relates to the fields of spintronics, sensor technology, thin film material preparation technology and the like, in particular to a ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film and a preparation method thereof.
Background
Magnetic Tunnel Junctions (MTJs) have promising prospects as spintronics in the fields of magnetic field sensors, magnetic storage, nanooscillators, neural network computation and the like.The traditional magnetic tunnel junction taking metal oxide (such as AlOx and MgO) as a barrier layer has the maximum magnetoresistance change rate TMR of about 600 percent, and cannot meet the requirements of small-sized and high-sensitivity weak magnetic detection. Due to the appearance of two-dimensional materials such as graphene and the like and the rapid development of the preparation process of the micro-nano device, the MTJ has new activity, and the TMR of the graphene-based magnetic tunnel junction can be up to 10 through theoretical prediction 5 Percent and can be regulated and controlled by the layer number. However, the novel spintronic device has extremely strong dependence on the characteristics of the graphene-ferromagnetic epitaxial interface. In the early stage, the problems of interface oxidation, impurity adsorption, non-epitaxy and the like easily exist by adopting a layer-by-layer growth preparation method based on transfer graphene and a double-sided deposition method based on suspension graphene, so that the characteristics of an epitaxial interface cannot be obtained, and the theoretical expected effect cannot be realized.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film with interface lattice epitaxial characteristics and a preparation method thereof.
In order to solve the technical problems, the invention adopts the following technical scheme:
the utility model provides a ferromagnetism/graphite alkene/ferromagnetism heteroepitaxy film, includes graphite alkene layer and the heterogeneous ferromagnetic layer of second and the first heterogeneous ferromagnetic layer that is located graphite alkene layer upper and lower surface respectively, graphite alkene layer directly epitaxial growth obtains on first heterogeneous ferromagnetic layer, the heterogeneous ferromagnetic layer of second epitaxial growth obtains on graphite alkene layer.
As a further improvement to the above technical solution:
the first heterogeneous ferromagnetic layer and/or the second heterogeneous ferromagnetic layer are ferromagnetic material layers which have single crystal structure characteristics and are matched with the lattice constant of graphene; the lattice symmetry of the ferromagnetic material of the second heterogeneous ferromagnetic layer is identical to the lattice symmetry of the ferromagnetic material of the first heterogeneous ferromagnetic layer.
The ferromagnetic material is nickel or cobalt.
The graphene layer is a single layer.
As a general inventive concept, the present invention also provides a method for preparing a ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film, comprising the steps of:
s1, growing a first heterogeneous ferromagnetic layer on an insulating substrate which is preprocessed and has hexagonal lattice attributes;
s2, preprocessing the first heterogeneous ferromagnetic layer to make the first heterogeneous ferromagnetic layer single-crystallized;
s3, taking a single-crystallized first heterogeneous ferromagnetic layer as a metal catalytic substrate, placing the metal catalytic substrate in a chemical vapor deposition system, and under the protective atmosphere of inert gas, hydrogen and carbon source gas, and at the temperature of 750-950 ℃, directly inducing a graphene layer to epitaxially grow on the first heterogeneous ferromagnetic layer by using a crystal surface potential field of the first heterogeneous ferromagnetic layer to obtain a ferromagnetic/graphene heteroepitaxial film;
s4, utilizing a crystal surface potential field of the first heterogeneous ferromagnetic layer to perform trans-boundary induced epitaxial growth on the graphene layer to form a second heterogeneous ferromagnetic layer;
and S5, annealing the second heterogeneous ferromagnetic layer to enable the second heterogeneous ferromagnetic layer to be single-crystallized, and obtaining the ferromagnetic/graphene/ferromagnetic heteroepitaxial film.
As a further improvement to the above technical solution:
in the step S1, a first heterogeneous ferromagnetic layer is grown on an insulating substrate by adopting an electron beam evaporation method; during the growth process, the vacuum degree is less than 5 multiplied by 10 -4 Pa, the temperature of the insulating substrate is between room temperature and 600 ℃, and the deposition rate is 0.05-0.5 nm/s.
In the step S4, a second heterogeneous ferromagnetic layer is induced and epitaxially grown on the graphene layer by adopting an electron beam evaporation method; during the growth process, the vacuum degree is less than 5X 10 -4 Pa, the substrate temperature is 300-350 ℃, and the deposition rate is 0.05-0.5 nm/s.
In the step S1, the pretreatment is annealing treatment, the temperature of the annealing treatment is 1000-1300 ℃, and the atmosphere of the annealing treatment is mixed gas of oxygen and inert gas.
In the step S2, the pretreatment is annealing treatment, the protective atmosphere is mixed gas of hydrogen and inert gas, the temperature is 800-1000 ℃, and the time is 0.5-2 h.
The insulating substrate is alpha-Al 2 O 3 (0001) A substrate or a MgO (111) substrate.
In the step S5, the temperature of the insulating substrate is 400-500 ℃ and the time is 0.5-2 h during the annealing treatment.
Compared with the prior art, the invention has the advantages that:
1. compared with the conventional graphene-ferromagnetic interface formed by coupling Van der Waals force by transferring graphene, the ferromagnetic/graphene/ferromagnetic hetero-epitaxial film has the advantages that orbital hybridization is generated between graphene and ferromagnetic material atoms, the interface spin filtering effect of graphene and ferromagnetic material is enhanced, the huge tunnel magnetoresistance change rate can be realized, and the performances of a graphene magnetic sensor and a related spin electronic device are greatly improved.
2. The preparation method of the invention comprises the steps of growing a first heterogeneous ferromagnetic layer on an insulating substrate with hexagonal lattice symmetry; utilizing a crystal surface potential field of the first heterogeneous ferromagnetic layer to directly induce epitaxial growth of a graphene layer on the first heterogeneous ferromagnetic layer; and carrying out graphene-crossing induced epitaxial growth on the graphene layer by utilizing the surface potential field of the first heterogeneous layer crystal to form a second heterogeneous ferromagnetic layer. The surface potential field of the first heterogeneous ferromagnetic layer is utilized to respectively carry out direct induction and cross-boundary induction growth on the graphene layer and the second heterogeneous ferromagnetic layer, so that the epitaxial characteristic of interface crystal lattices is ensured, the problems of interface oxidation, impurity adsorption, non-epitaxy and the like easily existing in the traditional preparation method can be effectively avoided, the high-quality preparation of the designed ferromagnetic/graphene/ferromagnetic heterogeneous epitaxial film can be realized, and a technical basis is provided for developing high-performance graphene-based magnetic sensors and other high-performance graphene spin electronic devices.
Drawings
Fig. 1 shows the results of molecular dynamics simulation growth of the ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film of the present invention.
Fig. 2 is a schematic structural diagram of a nickel/graphene/nickel heteroepitaxial thin film in embodiment 1 of the present invention.
Fig. 3 is a schematic flow chart of the preparation process of the nickel/graphene/nickel heteroepitaxial thin film in embodiment 1 of the present invention.
FIG. 4 is a graph showing the surface cleanliness and roughness characteristics of the upper nickel single crystal thin film according to example 1 of the present invention.
Fig. 5 is an interface characterization of the nickel/graphene/nickel heteroepitaxial thin film prepared in example 1.
Illustration of the drawings: 1. an insulating substrate; 2. a first heterogeneous ferromagnetic layer; 3. a graphene layer; 4. a second heterogeneous ferromagnetic layer.
Detailed Description
The invention will be described in further detail below with reference to the drawings and specific examples. Unless otherwise indicated, the instruments or materials employed in the practice of the present invention are commercially available.
The utility model provides a ferromagnetism/graphite alkene/ferromagnetism heteroepitaxial thin film, includes graphite alkene layer 3 and is located the second heterogeneous ferromagnetic layer 4 and the first heterogeneous ferromagnetic layer 2 of graphite alkene layer 3 upper and lower surface respectively, and graphite alkene layer 3 directly epitaxial growth obtains on first heterogeneous ferromagnetic layer 2, and the epitaxial growth of second heterogeneous ferromagnetic layer 4 obtains on graphite alkene layer 3. Compared with the conventional graphene-ferromagnetic interface formed by coupling Van der Waals force by transferring graphene, the ferromagnetic/graphene/ferromagnetic hetero-epitaxial film has the advantages that orbital hybridization is generated between graphene and ferromagnetic material atoms, the interface spin filtering effect of graphene and ferromagnetic material is enhanced, the huge tunnel magnetoresistance change rate can be realized, and the performances of a graphene magnetic sensor and related spin electronic devices are greatly improved.
The first and/or second ferromagnetic layer 2, 4 is a ferromagnetic material layer having a single crystal structure characteristic and matching with the lattice constant of graphene; the lattice symmetry of the ferromagnetic material of the second heterogeneous ferromagnetic layer 4 is identical to the lattice symmetry of the ferromagnetic material of the first heterogeneous ferromagnetic layer 2.
The ferromagnetic material is nickel or cobalt.
The graphene layer 3 is a single layer.
The ferromagnetic/graphene/ferromagnetic hetero-epitaxial film of the present embodiment is a nickel/graphene/nickel magnetic multilayer film having two epitaxial interfaces, as shown in fig. 2, and includes an insulating substrate 1 of α -Al 2 O 3 (0001) The substrate, the first heterogeneous ferromagnetic layer 2 is a lower nickel (111) single crystal film, the graphene layer 3 is a single-layer graphene layer grown by a CVD method, and the second heterogeneous ferromagnetic layer 4 is an upper nickel (111) single crystal film grown by a graphene-crossing heteroepitaxy method.
The ferromagnetic material has hexagonal symmetry lattice property and good matching property with graphene lattice property, highly oriented graphene is generated by catalysis, the insulating substrate is a substrate which has lattice symmetry consistency with the first heterogeneous ferromagnetic layer or the second heterogeneous ferromagnetic layer, and the first heterogeneous ferromagnetic layer or the second heterogeneous ferromagnetic layer is induced to have lattice orientation.
In this embodiment, the lower layer nickel (111) single crystal thin film is preferably 300nm thick in alpha-Al having hexagonal lattice 2 O 3 (0001) Prepared on a substrate having a size of 2 inches.
In this embodiment, graphene is grown on the lower nickel (111) single crystal thin film by an atmospheric pressure CVD method.
In this embodiment, the upper nickel (111) single crystal film is grown by trans-boundary induced heteroepitaxy: the method comprises two steps of film deposition and high-temperature annealing, and the upper layer nickel (111) single crystal film is preferably 5nm thick.
The invention relates to a preparation method of a ferromagnetic/graphene/ferromagnetic heteroepitaxial film, which comprises the following steps:
s1, growing a first heterogeneous ferromagnetic layer 2 on an insulating substrate 1 which is preprocessed and has hexagonal lattice attributes;
s2, preprocessing the first heterogeneous ferromagnetic layer 2 to make the first heterogeneous ferromagnetic layer 2 single-crystallized;
s3, taking the single-crystallized first heterogeneous ferromagnetic layer 2 as a metal catalytic substrate, placing the metal catalytic substrate in a chemical vapor deposition system, and directly inducing epitaxial growth of a graphene layer 3 on the first heterogeneous ferromagnetic layer 2 by using a crystal surface potential field of the first heterogeneous ferromagnetic layer 2 under the protective atmosphere of inert gas, hydrogen and carbon source gas at the temperature of 750-950 ℃ to obtain a ferromagnetic/graphene heterogeneous epitaxial film;
s4, utilizing the crystal surface potential field of the first heterogeneous ferromagnetic layer 2 to perform trans-boundary induced epitaxial growth on the graphene layer 3 to form a second heterogeneous ferromagnetic layer 4;
and S5, annealing the second heterogeneous ferromagnetic layer 4 to make the second heterogeneous ferromagnetic layer 4 single-crystallized, so as to obtain the ferromagnetic/graphene/ferromagnetic heteroepitaxial film.
According to the preparation method, the surface potential field of the first heterogeneous ferromagnetic layer 2 is utilized to respectively carry out direct induction and cross-boundary induction growth on the graphene layer 3 and the second heterogeneous ferromagnetic layer 4 (the simulated growth result is shown in figure 1), so that the epitaxial characteristic of an interface lattice is ensured, the problems of interface oxidation, impurity adsorption, non-epitaxy and the like easily existing in the traditional preparation method can be effectively avoided, the high-quality preparation of the designed ferromagnetic/graphene/ferromagnetic heterogeneous epitaxial film can be realized, and a technical basis is provided for developing high-performance graphene-based magnetic sensors and other high-performance graphene spinning electronic devices.
As shown in fig. 3, the method for preparing a ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film in this embodiment includes the following steps:
(1) Cleaning of the insulating substrate: 2 inch alpha-Al is selected 2 O 3 (0001) The substrate is an insulating substrate 1, the insulating substrate 1 is cleaned, placed in an acetone solution for ultrasonic cleaning for 5-10 minutes, placed in an isopropanol solution for ultrasonic cleaning for 5-10 minutes, placed in deionized water for ultrasonic cleaning for 5-10 minutes, and blown clean by a high-purity nitrogen gun. Each cleaning time in this example was 5min.
In other embodiments, the same or similar technical effects can be achieved by using the MgO (111) substrate as the insulating base.
(2) Annealing treatment of the insulating substrate: 2 inch alpha-Al 2 O 3 (0001) The substrate is put into a tubular annealing furnace for high-temperature annealing at 1000-1300 ℃ (1200 ℃ in the embodiment), and the annealing atmosphere is oxygen-argon mixed gas for annealing for 4 hours.
(3) Deposition of a lower nickel film: using electron beam evaporation at 2 inches of alpha-Al 2 O 3 (0001) Depositing a 300nm thick lower layer of nickel film, alpha-Al, on the substrate 2 O 3 The substrate is heated to a temperature ranging from room temperature to 600 deg.C (480 deg.C in this example) and the deposition rate is 0.05-0.5 nm/s (this example)Example 0.2 nm/s), a lower nickel film was obtained on the insulating substrate 1.
(4) Pretreatment of the lower layer nickel film: alpha-Al is added 2 O 3 (0001) Blowing the surface of the nickel film prepared on the substrate clean by a nitrogen gun, putting the nickel film into a tube furnace, and putting the nickel film into the tube furnace at 10 scmm H 2 And in the mixed atmosphere of 50 sccm Ar, heating to 850 ℃ at the speed of 20 ℃/min and maintaining for 2 hours, removing impurities on the surface of the nickel substrate, enabling the impurities to be subjected to (111) oriented single crystallization, and converting the lower-layer nickel film into a lower-layer nickel (111) single crystal film.
(5) And (3) graphene growth: introducing 1 sccm CH based on the atmosphere and temperature in the step (4) 4 As a graphene growth carbon source, the CH is closed after the carbon source is maintained for 38 min 4 And H 2 And the sliding heating furnace is rapidly cooled to room temperature to complete graphene growth (rapid cooling in this embodiment means that the sliding heating furnace is directly slid to naturally cool without the assistance of other cooling measures), and graphene is epitaxially grown on the lower-layer nickel film. Before the epitaxial deposition of the upper nickel film, the graphene/nickel/alpha-Al is treated 2 O 3 And (5) characterizing a sample, and ensuring that the surface of the graphene is clean, flat and free from wrinkles.
(6) Epitaxial deposition of an upper nickel film: adopting an electron beam evaporation method to perform on graphene/nickel/alpha-Al 2 O 3 And depositing an upper nickel film with the thickness of 5nm on the graphene of the sample, heating the substrate to 300-350 ℃ (320 ℃ in the embodiment), and obtaining the upper nickel film epitaxially grown on the graphene, wherein the deposition rate is 0.05-0.5 nm/s (0.05 nm/s in the embodiment).
(7) High-temperature annealing of the magnetic multilayer film: after the deposition process in the step (6) is finished, alpha-Al is added 2 O 3 Heating the substrate to 450 ℃, annealing for 1 hour to enable the epitaxially grown upper nickel film (111) to be oriented and single-crystallized, and obtaining the nickel/graphene/nickel heteroepitaxial film.
In this embodiment, the annealing in step (7) at 400 to 500 ℃ can also achieve single crystallization, because the upper layer nickel film is induced by the crystal lattice of the lower single crystal nickel film, and the annealing temperature can be lower than that of the lower layer nickel film.
The surface cleanliness and the roughness of the trans-graphene epitaxial nickel film are represented by means of an optical microscope, an atomic force microscope and the like, and the crystallization characteristic and the interface quality of the film are represented by a transmission electron microscope.
Fig. 4 is a result of surface cleanliness and roughness characterization of the magnetic multilayer film based on trans-boundary induced heteroepitaxy nickel/graphene/nickel prepared in this embodiment. Therefore, the epitaxial upper layer nickel single crystal film prepared by the embodiment has a clean and flat surface, and the roughness root mean square value is only 0.434 nm.
Fig. 5 is a transmission electron microscope characterization result of the trans-boundary induced hetero-epitaxial nickel/graphene/nickel-based magnetic multilayer film prepared in this embodiment. The crystal lattice of the upper layer nickel single crystal film is consistent with that of the lower layer nickel single crystal film, and the cross-graphene induced heteroepitaxy is realized.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present invention, or modify equivalent embodiments to equivalent variations, without departing from the scope of the invention, using the teachings disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention, unless the technical essence of the present invention departs from the content of the technical solution of the present invention.

Claims (7)

1. A ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film, characterized in that: the graphene-ferromagnetic epitaxial interface comprises a graphene layer (3), and a second heterogeneous ferromagnetic layer (4) and a first heterogeneous ferromagnetic layer (2) which are respectively positioned on the upper surface and the lower surface of the graphene layer (3), wherein the graphene layer (3) is obtained by directly epitaxially growing on the first heterogeneous ferromagnetic layer (2) by using a crystal surface potential field of the first heterogeneous ferromagnetic layer (2), and the second heterogeneous ferromagnetic layer (4) is obtained by cross-boundary induced epitaxial growth on the graphene layer (3) by using a crystal surface potential field of the first heterogeneous ferromagnetic layer (2);
the first and/or second heterogeneous ferromagnetic layers (2, 4) are ferromagnetic material layers having single crystal structure characteristics and matching with the lattice constant of graphene; the lattice symmetry of the ferromagnetic material of the second heterogeneous ferromagnetic layer (4) is identical to the lattice symmetry of the ferromagnetic material of the first heterogeneous ferromagnetic layer (2);
the ferromagnetic/graphene/ferromagnetic heteroepitaxial film is prepared by the following steps:
s1, growing a first heterogeneous ferromagnetic layer (2) on a preprocessed insulating substrate (1) with hexagonal lattice properties;
s2, preprocessing the first heterogeneous ferromagnetic layer (2) to make the first heterogeneous ferromagnetic layer (2) single-crystallized; in the step S2, the pretreatment is annealing treatment, the protective atmosphere is mixed gas of hydrogen and inert gas, the temperature is 800-1000 ℃, and the time is 0.5-2 h;
s3, taking the single-crystallized first heterogeneous ferromagnetic layer (2) as a metal catalytic substrate, placing the metal catalytic substrate in a chemical vapor deposition system, and under the protective atmosphere of inert gas, hydrogen and carbon source gas, at the temperature of 750-950 ℃, directly inducing epitaxial growth of a graphene layer (3) on the first heterogeneous ferromagnetic layer (2) by using a crystal surface potential field of the first heterogeneous ferromagnetic layer (2) to obtain a ferromagnetic/graphene heterogeneous epitaxial film;
s4, utilizing the crystal surface potential field of the first heterogeneous ferromagnetic layer (2) to perform trans-boundary induced epitaxial growth on the graphene layer (3) to form a second heterogeneous ferromagnetic layer (4); in the step S4, a second heterogeneous ferromagnetic layer (4) is induced and epitaxially grown on the graphene layer (3) by adopting an electron beam evaporation method; during the growth process, the vacuum degree is less than 5X 10 -4 Pa, the substrate temperature is 320 ℃, and the deposition rate is 0.05-0.5 nm/s;
s5, annealing the second heterogeneous ferromagnetic layer (4) to make the second heterogeneous ferromagnetic layer (4) single-crystallized to obtain a ferromagnetic/graphene/ferromagnetic heterogeneous epitaxial film; in the step S5, during the annealing treatment, the temperature of the insulating substrate is 400-500 ℃ and the time is 0.5-2 h.
2. The ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film of claim 1, wherein: the ferromagnetic material is nickel or cobalt.
3. The ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film of any one of claims 1 to 2, wherein: the graphene layer (3) is a single layer.
4. A method for the preparation of ferromagnetic/graphene/ferromagnetic heteroepitaxial thin film according to any one of claims 1 to 3, characterized in that: the method comprises the following steps:
s1, growing a first heterogeneous ferromagnetic layer (2) on a preprocessed insulating substrate (1) with hexagonal lattice properties;
s2, preprocessing the first heterogeneous ferromagnetic layer (2) to make the first heterogeneous ferromagnetic layer (2) single-crystallized; in the step S2, the pretreatment is annealing treatment, the protective atmosphere is mixed gas of hydrogen and inert gas, the temperature is 800-1000 ℃, and the time is 0.5-2 h;
s3, taking the single-crystallized first heterogeneous ferromagnetic layer (2) as a metal catalytic substrate, placing the metal catalytic substrate in a chemical vapor deposition system, and under the protective atmosphere of inert gas, hydrogen and carbon source gas, at the temperature of 750-950 ℃, directly inducing epitaxial growth of a graphene layer (3) on the first heterogeneous ferromagnetic layer (2) by using a crystal surface potential field of the first heterogeneous ferromagnetic layer (2) to obtain a ferromagnetic/graphene heterogeneous epitaxial film;
s4, utilizing the crystal surface potential field of the first heterogeneous ferromagnetic layer (2) to perform trans-boundary induced epitaxial growth on the graphene layer (3) to form a second heterogeneous ferromagnetic layer (4); in the step S4, a second heterogeneous ferromagnetic layer (4) is induced and epitaxially grown on the graphene layer (3) by adopting an electron beam evaporation method; during the growth process, the vacuum degree is less than 5X 10 -4 Pa, the substrate temperature is 320 ℃, and the deposition rate is 0.05-0.5 nm/s;
s5, annealing the second heterogeneous ferromagnetic layer (4) to make the second heterogeneous ferromagnetic layer (4) single-crystallized to obtain a ferromagnetic/graphene/ferromagnetic heterogeneous epitaxial film; in the step S5, the temperature of the insulating substrate is 400-500 ℃ and the time is 0.5-2 h during the annealing treatment.
5. The method of manufacturing according to claim 4, characterized in that: in the step S1, growing a first heterogeneous ferromagnetic layer (2) on an insulating substrate (1) by adopting an electron beam evaporation method; during the growth process, the vacuum degree is less than 5X 10 -4 Pa, the temperature of the insulating substrate is between room temperature and 600 ℃, and the deposition rate is 0.05-0.5 nm/s.
6. The method of manufacturing according to claim 4, characterized in that: in the step S1, the pretreatment is annealing treatment, the annealing treatment temperature is 1000-1300 ℃, and the annealing treatment atmosphere is mixed gas of oxygen and inert gas.
7. The method of claim 4, wherein: the insulating substrate is alpha-Al 2 O 3 (0001) A substrate or an MgO (111) substrate.
CN202010455831.3A 2020-05-26 2020-05-26 Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof Active CN111647942B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010455831.3A CN111647942B (en) 2020-05-26 2020-05-26 Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010455831.3A CN111647942B (en) 2020-05-26 2020-05-26 Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof

Publications (2)

Publication Number Publication Date
CN111647942A CN111647942A (en) 2020-09-11
CN111647942B true CN111647942B (en) 2022-10-11

Family

ID=72341521

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010455831.3A Active CN111647942B (en) 2020-05-26 2020-05-26 Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof

Country Status (1)

Country Link
CN (1) CN111647942B (en)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2834891A1 (en) * 2011-05-27 2012-12-06 University Of North Texas Graphene magnetic tunnel junction spin filters and methods of making
CN103268916B (en) * 2013-04-25 2015-06-10 中国科学院宁波材料技术与工程研究所 Method for preparing magnetic tunnel junction
CN103323796B (en) * 2013-06-21 2015-07-29 中国人民解放军国防科学技术大学 A kind of MTJ magnetic field sensor using Graphene as barrier layer
CN106711323A (en) * 2016-12-20 2017-05-24 清华大学 Magnetic heterostructure magnetic tunnel junction adopting two-dimensional material
CN109962157B (en) * 2017-12-25 2022-08-12 中国人民解放军国防科技大学 Spinning electronic device and preparation method thereof
CN108470765B (en) * 2018-03-21 2021-07-23 中国人民解放军国防科技大学 Graphene vertical heterojunction device and preparation method thereof
CN110616454B (en) * 2019-03-07 2020-10-09 北京大学 Method for vertical heteroepitaxy monocrystal metal film based on monocrystal two-dimensional material/monocrystal copper

Also Published As

Publication number Publication date
CN111647942A (en) 2020-09-11

Similar Documents

Publication Publication Date Title
JP4818754B2 (en) Method for producing silicon carbide single crystal ingot
JP5727017B2 (en) Method for graphene growth
JPS58130517A (en) Manufacture of single crystal thin film
Wang et al. Synthesis of large-area single-crystal graphene
US20090291523A1 (en) Method of Manufacturing High Quality ZnO Monocrystal Film on Silicon(111) Substrate
WO2003085175A1 (en) Seed crystal of silicon carbide single crystal and method for producing ingot using same
CN103227194B (en) Large-size graphene stack structure wafer and preparation method thereof
CN109440081B (en) Method for preparing magnetic graphene film based on chemical vapor deposition method
CN109205599B (en) Method for preparing graphene single crystal wafer at low temperature
Wang et al. Investigation of growth characteristics and semimetal–semiconductor transition of polycrystalline bismuth thin films
CN111647942B (en) Ferromagnetic/graphene/ferromagnetic hetero-epitaxial film and preparation method thereof
CN109913945A (en) A method of growing bismuth selenide high-index surface monocrystal thin films on silicon (211) substrate
JP4922336B2 (en) Method for producing iron silicide nanowire
KR100821267B1 (en) Method for manufacturing bi nanowire by using stress-induced growth
JP2012121778A (en) Graphene and method for producing the same
JP3657036B2 (en) Silicon carbide thin film and method for manufacturing silicon carbide thin film laminated substrate
CN1395291A (en) Double buffer layer process for radio-frequency plasma molecular beam epitaxial growth of gallium nitride
CN103541000A (en) Device and method for preparing boron nitride single crystal
CN111606322B (en) Ferromagnetic thin film epitaxial single-layer graphene and preparation method thereof
CN107500276B (en) Method for preparing ultra-clean graphene by using copper acetate
CN114107941B (en) Method for growing layer thickness-controllable graphene on monocrystalline ferromagnetic film substrate
CN102162135A (en) Preparation method of ZnS/Si nuclear-shell nanowires or nanobelts and polycrystal Si tubes
CN106702482B (en) A method of growing indium stibide film on a silicon substrate
CN111705359A (en) Method for preparing graphene single crystal wafer on copper-based textured film substrate
JPH0342818A (en) Compound semiconductor device and its manufacture

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant