Growth method of high-quality La2NiMnO6 single crystal film
Through pulsed laser deposition and annealing treatment, the high-quality growth of the La2NiMnO6 single crystal film is achieved under limited equipment conditions, solving the problem of expensive and difficult to obtain equipment, reducing manufacturing costs and improving the physical properties of the film.
Patent Information
- Application Number
- CN202411235049.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-04
- Publication Date
- 2024-12-13
AI Technical Summary
Dual perovskite transition metal oxide La2NiMnO6 requires equipment with high temperature and high oxygen pressure when achieving high-quality growth. However, these equipment are expensive and difficult to obtain, limiting their high-quality single crystal film thin growth under limited equipment conditions. .
The La2NiMnO6 film was grown at a high temperature of 900°C under a low oxygen partial pressure of 200 mT, and the high oxygen pressure annealing treatment was performed after deposition to achieve the growth of high-quality La2NiMnO6 single crystal film thin.
The equipment conditions limitations were successfully overcome, the material manufacturing cost was reduced, and a high-quality La2NiMnO6 single crystal thin film was grown on a strontium titanate (SrTiO3) substrate, and the film quality was further improved by adjusting the growth parameters.
Smart Images
Figure CN119121400A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of transition metal oxide semiconductors, and in particular to a method for growing high-quality double perovskite transition metal oxides whose carrier is a single crystal La2NiMnO6 film. Background Art
[0002] In recent years, the rapid growth of energy demand and the rapid change of global climate have driven the development of clean energy application technology in a more eco-friendly direction. Multifunctional materials with both electrical and magnetic order have been produced, which is driven by the growing demand for next-generation electronic devices with low energy consumption and high operating speed. Transition metal oxide materials have rich physical properties due to the strong correlation of d-orbital electrons and the diversity of valence states. Their flexible and changeable structures give them a variety of physical properties, making them the best choice for realizing next-generation electronic devices. Double perovskite La2NiMnO6 is a high ferromagnetic transition temperature (T C =280K) and a wide bandgap (4.4eV) semiconductor. It has both semiconductor and magnetic properties and is one of the few low-cost materials. Therefore, La2NiMnO6 is expected to be one of the material choices for the next generation of electronic devices. However, the double perovskite transition metal oxide La2NiMnO6 faces the following difficulties in achieving high-quality growth: La2NiMnO6 needs to be grown under high temperature (above 800°C) and high oxygen partial pressure (above 500mT) conditions to achieve high-quality thin film growth. However, equipment with both high temperature and high oxygen pressure is expensive and difficult to purchase. Therefore, it is hoped that high-quality La2NiMnO6 single crystal thin film growth can be achieved under limited equipment conditions.
[0003] The present invention adopts a pulsed laser deposition (PLD) growth method, and performs a high oxygen pressure annealing treatment after film deposition under the growth conditions of a high temperature of 900°C but a low oxygen partial pressure of 200mT, thereby successfully realizing a high-quality La2NiMnO6 single crystal thin film growth method, thereby solving the problem of equipment condition limitations. Summary of the invention
[0004] The purpose of the present invention is to solve the above problems in the prior art and to provide a method for growing high-quality La2NiMnO6 single crystal thin films. When the growth equipment cannot simultaneously meet the growth conditions of high temperature and high oxygen pressure, high-quality growth of La2NiMnO6 single crystal thin films can be achieved.
[0005] In order to achieve the above object, the present invention adopts the following technical scheme:
[0006] A method for growing a high-quality La2NiMnO6 single crystal thin film comprises the following steps:
[0007] 1) Cleaning the strontium titanate (SrTiO3) single crystal substrate;
[0008] 2) La2NiMnO6 thin film is deposited on strontium titanate substrate using pulsed laser deposition growth method;
[0009] 3) The La2NiMnO6 film deposited in step 2) is placed in a high oxygen pressure gas atmosphere for annealing, thereby completing the preparation of high-quality La2NiMnO6 single crystal film.
[0010] In step 1), the strontium titanate substrate is ultrasonically cleaned in deionized water and then wiped with a cotton swab dipped in alcohol. After wiping with the cotton swab, the surface of the substrate is observed through a microscope until no particles of dirt are observed under the microscope.
[0011] Step 2) In the pulse laser deposition growth method, the growth parameters are: growth temperature 750-900°C, growth oxygen partial pressure not less than 200mT; preferably 900°C.
[0012] Step 3) annealing parameters are: annealing temperature not less than 600° C., annealing oxygen pressure not less than 20000 Pa, and annealing time not less than 2 h.
[0013] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:
[0014] The present invention uses a pulsed laser deposition method to achieve high-quality La2NiMnO6 single crystal film growth on a strontium titanate (SrTiO3) substrate. In order to achieve higher quality La2NiMnO6 single crystal film, in addition to relying on high oxygen partial pressure and high temperature growth conditions, higher quality La2NiMnO6 single crystal film growth can also be achieved by adjusting the target-substrate distance, laser energy density, laser repetition frequency, annealing time, and annealing oxygen pressure.
[0015] The present invention successfully overcomes the limitation of growth equipment conditions and grows high-quality double perovskite material La2NiMnO6 single crystal thin film on strontium titanate (SrTiO3) substrate. Due to the successful overcoming of the limitation of growth equipment conditions, the manufacturing cost of the material is significantly reduced, and it is not dependent on expensive and difficult to purchase equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is the X-ray diffraction (XRD) pattern of the La2NiMnO6 single crystal thin film prepared in Example 1.
[0017] Figure 2This is an X-ray absorption spectrum (XAS) test diagram of the La2NiMnO6 single crystal film prepared in Example 1, and is a Ni L-Edge diagram of XAS.
[0018] Figure 3 This is an X-ray absorption spectrum (XAS) test diagram of the La2NiMnO6 single crystal film prepared in Example 1, and is a Mn L-Edge diagram of the XAS.
[0019] Figure 4 This is the X-ray absorption spectrum (XAS) test diagram of the La2NiMnO6 single crystal film prepared in Example 1, which is the OK-Edge diagram of XAS.
[0020] Figure 5 This is the XRD pattern of the sample prepared in Comparative Example 1. DETAILED DESCRIPTION
[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0022] Example 1
[0023] 1) Select a strontium titanate (SrTiO3) single crystal (001) and a single-side polished strontium titanate substrate with a size of 5mm×5mm×0.5mm. First, ultrasonically clean the strontium titanate (SrTiO3) in deionized water for 10 minutes, and then wipe it with a cotton swab dipped in alcohol until it is wiped clean to serve as the substrate.
[0024] 2) La2NiMnO6 thin film was deposited on SrTiO3 substrate using pulsed laser deposition (PLD) growth method. The growth parameters of pulsed laser deposition (PLD) method are: growth temperature (750℃~900℃), growth oxygen partial pressure (200mT), target-substrate distance (56.6mm), laser energy density (1.5J / cm 2 ), laser repetition frequency (2H Z ), target material La2NiMnO6.
[0025] The La2NiMnO6 film deposited in step 2) is annealed in a high oxygen pressure atmosphere, and the annealing parameters are: annealing temperature (600°C), annealing oxygen pressure (20000Pa), and annealing time (2h), thereby completing the preparation of high-quality La2NiMnO6 single crystal film.
[0026] Comparative Example 1
[0027] On the basis of Example 1, the annealing time of the annealing parameters was set to 1 h, and other parameters remained unchanged.
[0028] Figure 1 The X-Ray diffractometer characterization spectrum of La2NiMnO6 single crystal thin film samples, by comparing different growth temperatures (from 750 ~ 900 ℃), found that the half width height of the XRD spectrum of La2NiMnO6 single crystal thin film grown at 900 ℃ is the smallest, and the thickness stripes (high film quality characteristics) appear in the XRD spectrum of La2NiMnO6 single crystal thin film grown under 900 ℃, which indicates that high-quality La2NiMnO6 single crystal thin film growth has been achieved. It can be learned from the references that in the high-quality La2NiMnO6 single crystal thin film material system, the valence states of Ni and Mn are +2 and +4, respectively.
[0029] Figure 2 and Figure 3 The XAS Ni L-Edge diagram and the XAS Mn L-Edge diagram are respectively the X-ray absorption spectrum (XAS) test diagrams of the La2NiMnO6 single crystal film prepared in Example 1. By comparing the results of the reference literature, it can be determined that the valence states of Ni and Mn in the LNMO film grown by the present invention are +2 and +4 respectively; Figure 4 In the XAS O K-Edge spectrum, it can be seen that the film prepared under the growth condition of 900°C has a stronger Mn / Ni 3d–O 2p hybridization. The above experimental results consistently show that the growth method of the present invention achieves the growth of high-quality La2NiMnO6 single crystal films.
[0030] from Figure 5 It can be seen that under the condition of annealing for 1h, the crystals grown at 750℃ and 800℃ are not pure and contain impure crystals. Single crystals are grown at 850℃ and 900℃, but since there are no thickness fringes in the XRD spectrum, high-quality crystals are not grown. Figure 1 In Example 1, under the condition of annealing for 2h, single crystals were grown at 750℃, 800℃ and 850℃, but no thickness fringes appeared in the XRD spectrum, so high-quality crystals were not grown. In the single crystal grown at 900℃, thickness fringes appeared in the XRD spectrum, indicating that high-quality crystals were grown.
[0031] The present invention adopts a pulse laser deposition (PLD) growth method plus annealing treatment to successfully realize the preparation of high-quality La2NiMnO6 single crystal thin film.
Claims
1. A method for growing high-quality La2NiMnO6 single crystal thin films, characterized in that: The following steps are involved: 1) Clean the strontium titanate substrate; 2) La2NiMnO6 thin film is deposited on strontium titanate substrate using pulsed laser deposition growth method; 3) The La2NiMnO6 film deposited in step 2) is placed in a high oxygen pressure gas atmosphere for annealing, thereby completing the preparation of high-quality La2NiMnO6 single crystal film.
2. A method for growing a high-quality La2NiMnO6 single crystal thin film as claimed in claim 1, characterized in that: In step 1), the strontium titanate substrate is ultrasonically cleaned in deionized water and then wiped with a cotton swab dipped in alcohol. After wiping with the cotton swab, the surface of the substrate is observed through a microscope until no particles of dirt are observed under the microscope.
3. A method for growing a high-quality La2NiMnO6 single crystal thin film as claimed in claim 1, characterized in that: Step 2) In the pulse laser deposition growth method, the growth parameters are: growth temperature 750-900°C, growth oxygen partial pressure not less than 200mT.
4. A method for growing a high-quality La2NiMnO6 single crystal thin film as claimed in claim 3, characterized in that: The growth temperature is 900°C.
5. A method for growing a high-quality La2NiMnO6 single crystal thin film as claimed in claim 1, characterized in that: Step 3) annealing parameters are: annealing temperature not less than 600° C., annealing oxygen pressure not less than 20000 Pa.
6. A method for growing a high-quality La2NiMnO6 single crystal thin film as claimed in claim 1, characterized in that: Step 3) annealing time is not less than 2h.