CN115557789A - Preparation method and application of a flexible transition metal oxide lanthanum strontium manganese iron oxide magnetic thick film - Google Patents

Abstract

The invention relates to the technical field of ferromagnetic materials, in particular to a flexible transition metal oxide lanthanum strontium manganese ferromagnetic thick film, a preparation method and its application. The lattices are coupled to each other, have good ferromagnetism, huge magnetoresistance effect, conductivity, etc., and have the advantages of low energy consumption, fast reading speed, and long life. The LSMO thick film is also a perovskite oxide. Oxygen ions interact with transition metal ions, resulting in many characteristics of its electronic behavior, especially good conductivity, which can provide a new potential application for metal oxide electrodes. At the same time, due to the influence of electric field, magnetic field, interface, etc., the film has more possibilities for its application.

Description

A method for preparing a flexible transition metal oxide lanthanum strontium manganese iron oxide magnetic thick film and its application

technical field

The invention relates to the technical field of ferromagnetic materials, in particular to a flexible transition metal oxide lanthanum strontium manganese ferromagnetic thick film, a preparation method and an application thereof.

Background technique

In this ever-growing society, computers are developing rapidly, the speed of information dissemination becomes faster and the scope of dissemination is wider, and human beings have thus entered the information age, which further requires our devices to keep up with the development of the times. Since the advent of semiconductor transistors, they have appeared in a wide variety of industrial products due to their unique characteristics. In our daily life, TVs, cars, air conditioners, etc., especially semiconductor devices in memory, are widely used. The traditional large-scale information industry can no longer meet the requirements of the current era, and microelectronic devices are gradually developing towards miniaturization and integration. But nowadays semiconductor technology is improving very slowly, which requires a new material or new process to meet the requirements of contemporary people. Due to their excellent properties, transition metal oxides are considered to be new materials that can replace silicon in next-generation semiconductor devices.

Transition metal oxides are perovskite-type oxides. Because of the interaction between oxygen ions and transition metal ions, the charges, spins, orbits, and lattices are coupled to each other, which induces ferromagnetism. . Among them, the spin of electrons has two orientations, up and down, which can be used as a medium for information storage and processing in ferromagnetic materials. Ferromagnetic materials are also widely concerned because of their unique physical properties, which bring new research directions for magnetoelectric coupling and electric field-regulated magnetization dynamics, which are of great significance for both basic research and practical applications.

In view of the above-mentioned defects, the creator of the present invention has finally obtained the present invention through long-term research and practice.

Contents of the invention

The purpose of the present invention is to solve the problem of how to obtain a ferromagnetic material with good ferromagnetism, conductivity and excellent performance, and provides a flexible transition metal oxide lanthanum strontium manganese ferromagnetic thick film, a preparation method and its application.

In order to achieve the above object, the present invention discloses a flexible transition metal oxide lanthanum strontium manganese ferromagnetic thick film, the chemical general formula of the flexible transition ferromagnetic metal oxide lanthanum strontium manganese ferromagnetic thick film is La _0.7 Sr _0.3 MnO ₃ .

The thickness of the flexible transition ferromagnetic metal oxide lanthanum strontium manganese ferromagnetic thick film is 10-20 μm.

The present invention also discloses a preparation method of the flexible transition ferromagnetic metal oxide lanthanum strontium manganese ferromagnetic thick film, which includes the following steps:

S1, measure lanthanum oxide, strontium carbonate, and manganese oxide according to the general chemical formula of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film, mix the mixed powder, ball milling medium, and alcohol for ball milling;

S2, drying the ball-milled powder obtained in step S1, pre-calcining and heat-preserving the dried powder, then grinding the powder, and obtaining a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ powder after drying ;

S3, fully mixing the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ powder with an organic solvent to obtain a slurry of a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film;

S4, defoaming the slurry obtained in step S3, then casting it into a film, and obtaining a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film after drying.

The ball milling medium in the step S1 is agate balls, and the diameter of the agate balls is 2-10 mm.

During the ball milling in the step S1, the mass ratio of the mixed powder, the ball milling medium, and the alcohol is 1:1.5:1, and the ball milling time is 24 hours.

In the step S2, the drying temperature is 60-100° C., and the drying time is 6-12 hours.

In the step S2, the calcining temperature is 650-1050° C., the holding time is 2-8 hours, the ball milling time is 24 hours, and the drying time is 6-12 hours.

In the step S3, the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ powder is first mixed with an organic solvent, a dispersant and zirconia balls, and mixed for 200-300 minutes to obtain a preliminary slurry, which is mixed with a binder , homogenizer, and mix for 200 to 300 minutes to obtain the final slurry. The organic solvent is toluene-ethanol, the dispersant is glyceryl trioleate, the binder is polyethylene glycol, and the homogenizer is o- Butyl phthalate.

In the step S4, the defoaming is carried out by a vacuum defoaming machine, and the defoaming time is 25-60 minutes.

The invention also discloses the application of the flexible transition metal oxide lanthanum strontium manganese ferrite thick magnetic film in semiconductor devices.

Compared with the prior art, the beneficial effect of the present invention lies in: the LSMO thick film prepared by the casting method of the present invention has high density, good ductility and relatively strong plasticity. The preparation process of the present invention is simple, and the prepared thick film has good ferromagnetism, huge magnetoresistance effect, conductivity, etc. due to the mutual coupling between spin, charge, orbit and lattice in LSMO, and the device thus prepared will have The advantages of low energy consumption, fast reading speed and long life. The prepared thick film has good ferromagnetism, huge magnetoresistance effect, conductivity, etc. due to the mutual coupling between spin, charge, orbit, and lattice in LSMO. The flexible ferromagnetic metal oxide LSMO thick film prepared by the present invention is also a perovskite oxide, and due to the addition of oxygen ions, it interacts with transition metal ions, causing its electronic behavior to have many characteristics. In particular, it has good electrical conductivity, which can provide a new idea for the potential application of metal oxide electrodes. At the same time, the film will have more possibilities for its application due to the influence of electric field, magnetic field, interface, etc.

Description of drawings

Figure 1 is the XRD pattern of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film at different pre-firing temperatures;

Fig. 2 is the SEM image of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film at different pre-firing temperatures and Comparative Example 3;

Fig. 3 is the energy spectrum of flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film at different pre-firing temperatures and comparative example 3;

Fig. 4 is the hysteresis curve of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film and comparative examples 1, 2, and 3 at 10K;

Figure 5 shows the MT curves of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film and Comparative Examples 1 and 2.

detailed description

The above and other technical features and advantages of the present invention will be described in more detail below in conjunction with the accompanying drawings.

Example 1

This embodiment provides a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film, wherein the preparation method of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film is as follows:

S1: Preparation of La _0.7 Sr _0.3 MnO ₃ powder.

S2: Preparation of La _0.7 Sr _0.3 MnO ₃ thick film.

According to an example of the present invention, the specific operation of S1 is as follows:

S101: According to their general chemical formula, weigh lanthanum oxide (99.99%), strontium carbonate (99%), manganese dioxide (99.8%), barium titanate (99%), titanium dioxide powder (100%) respectively, weigh After it is ready, put it in the ball mill pot according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1, set the speed of the planetary ball mill to 400rpm, and the ball milling time is 24h. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S102: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C.

S103: Pre-fire the dried mixed powder, put it in an alumina crucible, then put it in a tube furnace, supply oxygen, set the temperature from room temperature to 650°C, keep it warm for 4 hours, and the heating rate is 3°C /min, the cooling rate is 5°C/min, when the temperature drops to 500°C, it will be cooled to room temperature with the furnace.

S104: Take out the pre-burned La _0.7 Sr _0.3 MnO ₃ powder, crush it with an agate mortar, and place it in a ball mill jar according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1 . The rotation speed of the planetary ball mill is set to 400 rpm, and the ball milling time is 24 hours. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S105: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C. After drying, dry La _0.7 Sr _0.3 MnO ₃ powder can be obtained.

According to an example of the present invention, the specific operation of S2 is as follows:

S201: Mix the dried powder with the organic solvent toluene-ethanol and the dispersant triolein, add zirconia balls, and put them into a three-dimensional powder mixer to mix the powder, wherein, the powder mass: zirconia ball mass: Solvent mass: dispersant mass = 18:27:25:2. The powder mixing time is 240min, and the preliminary slurry is obtained

S202: Add polyethylene glycol, phthalate diester and polyvinyl butylate to the preliminary slurry, wherein the mass ratio is, original powder: polyethylene glycol: phthalate diester: polyethylene Butyl alcohol = 18:10:3:5. Then mix the powder for 360 minutes to get the final slurry.

S203: Use a vacuum defoaming machine to perform defoaming treatment on the slurry for 40 minutes, and then cast the defoamed slurry into a film through a casting machine with a knife adjustment of 200 and a casting rate of 20cm/min , after drying at room temperature for 4 hours, a La _0.7 Sr _0.3 MnO ₃ thick film can be obtained.

Example 2

This embodiment provides a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film, wherein the preparation method of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film is as follows:

S1: Preparation of La _0.7 Sr _0.3 MnO ₃ powder.

S2: Preparation of La _0.7 Sr _0.3 MnO ₃ thick film.

According to an example of the present invention, the specific operation of S1 is as follows:

S101: According to their general chemical formula, weigh lanthanum oxide (99.99%), strontium carbonate (99%), manganese dioxide (99.8%), barium titanate (99%), titanium dioxide powder (100%) respectively, weigh After it is ready, put it in the ball mill pot according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1, set the speed of the planetary ball mill to 400rpm, and the ball milling time is 24h. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S102: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C.

S103: Pre-fire the dried mixed powder, put it in an alumina crucible, then place it in a tube furnace, supply oxygen, set the temperature from room temperature to 750°C, keep it warm for 4 hours, and the heating rate is 3°C /min, the cooling rate is 5°C/min, when the temperature drops to 500°C, it will be cooled to room temperature with the furnace.

S104: Take out the pre-burned La _0.7 Sr _0.3 MnO ₃ powder, crush it with an agate mortar, and place it in a ball mill jar according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1 . The rotation speed of the planetary ball mill is set to 400 rpm, and the ball milling time is 24 hours. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S105: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C. After drying, dry La _0.7 Sr _0.3 MnO ₃ powder can be obtained.

According to an example of the present invention, the specific operation of S2 is as follows:

S201: Mix the dried powder with the organic solvent toluene-ethanol and the dispersant triolein, add zirconia balls, and put them into a three-dimensional powder mixer to mix the powder, wherein, the powder mass: zirconia ball mass: Solvent mass: dispersant mass = 18:27:25:2. The powder mixing time is 240min, and the preliminary slurry is obtained

S202: Add polyethylene glycol, phthalate diester and polyvinyl butylate to the preliminary slurry, wherein the mass ratio is, original powder: polyethylene glycol: phthalate diester: polyethylene Butyl alcohol = 18:10:3:5. Then mix the powder for 360 minutes to get the final slurry.

S203: Use a vacuum defoaming machine to perform defoaming treatment on the slurry for 40 minutes, and then cast the defoamed slurry into a film through a casting machine with a knife adjustment of 200 and a casting rate of 20cm/min , after drying at room temperature for 4 hours, a La _0.7 Sr _0.3 MnO ₃ thick film can be obtained.

Example 3

This embodiment provides a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film, wherein the preparation method of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film is as follows:

S1: Preparation of La _0.7 Sr _0.3 MnO ₃ powder.

S2: Preparation of La _0.7 Sr _0.3 MnO ₃ thick film.

According to an example of the present invention, the specific operation of S1 is as follows:

S101: According to their general chemical formula, weigh lanthanum oxide (99.99%), strontium carbonate (99%), manganese dioxide (99.8%), barium titanate (99%), titanium dioxide powder (100%) respectively, weigh After it is ready, put it in the ball mill pot according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1, set the speed of the planetary ball mill to 400rpm, and the ball milling time is 24h. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S102: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C.

S103: Pre-fire the dried mixed powder, put it in an alumina crucible, then put it in a tube furnace, supply oxygen, set the temperature from room temperature to 850°C, keep it warm for 4 hours, and the heating rate is 3°C /min, the cooling rate is 5°C/min, when the temperature drops to 500°C, it will be cooled to room temperature with the furnace.

S104: Take out the pre-burned La _0.7 Sr _0.3 MnO ₃ powder, crush it with an agate mortar, and place it in a ball mill jar according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1 . The rotation speed of the planetary ball mill is set to 400 rpm, and the ball milling time is 24 hours. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S105: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C. After drying, dry La _0.7 Sr _0.3 MnO ₃ powder can be obtained.

According to an example of the present invention, the specific operation of S2 is as follows:

S201: Mix the dried powder with the organic solvent toluene-ethanol and the dispersant triolein, add zirconia balls, and put them into a three-dimensional powder mixer to mix the powder, wherein, the powder mass: zirconia ball mass: Solvent mass: dispersant mass = 18:27:25:2. The powder mixing time is 240min, and the preliminary slurry is obtained

S202: Add polyethylene glycol, phthalate diester and polyvinyl butylate to the preliminary slurry, wherein the mass ratio is, original powder: polyethylene glycol: phthalate diester: polyethylene Butyl alcohol = 18:10:3:5. Then mix the powder for 360 minutes to get the final slurry.

S203: Use a vacuum defoaming machine to perform defoaming treatment on the slurry for 40 minutes, and then cast the defoamed slurry into a film through a casting machine with a knife adjustment of 200 and a casting rate of 20cm/min , after drying at room temperature for 4 hours, a La _0.7 Sr _0.3 MnO ₃ thick film can be obtained.

Example 4

This embodiment provides a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film, wherein the preparation method of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film is as follows:

S1: Preparation of La _0.7 Sr _0.3 MnO ₃ powder.

S2: Preparation of La _0.7 Sr _0.3 MnO ₃ thick film.

According to an example of the present invention, the specific operation of S1 is as follows:

S101: According to their general chemical formula, weigh lanthanum oxide (99.99%), strontium carbonate (99%), manganese dioxide (99.8%), barium titanate (99%), titanium dioxide powder (100%) respectively, weigh After it is ready, put it in the ball mill pot according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1, set the speed of the planetary ball mill to 400rpm, and the ball milling time is 24h. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S102: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C.

S103: Pre-fire the dried mixed powder, put it in an alumina crucible, then put it in a tube furnace, supply oxygen, set the temperature from room temperature to 950°C, keep it warm for 4 hours, and the heating rate is 3°C /min, the cooling rate is 5°C/min, when the temperature drops to 500°C, it will be cooled to room temperature with the furnace.

S104: Take out the pre-burned La _0.7 Sr _0.3 MnO ₃ powder, crush it with an agate mortar, and place it in a ball mill jar according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1 . The rotation speed of the planetary ball mill is set to 400 rpm, and the ball milling time is 24 hours. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S105: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C. After drying, dry La _0.7 Sr _0.3 MnO ₃ powder can be obtained.

According to an example of the present invention, the specific operation of S2 is as follows:

S201: Mix the dried powder with the organic solvent toluene-ethanol and the dispersant triolein, add zirconia balls, and put them into a three-dimensional powder mixer to mix the powder, wherein, the powder mass: zirconia ball mass: Solvent mass: dispersant mass = 18:27:25:2. The powder mixing time is 240min, and the preliminary slurry is obtained

S202: Add polyethylene glycol, phthalate diester and polyvinyl butylate to the preliminary slurry, wherein the mass ratio is, original powder: polyethylene glycol: phthalate diester: polyethylene Butyl alcohol = 18:10:3:5. Then mix the powder for 360 minutes to get the final slurry.

S203: Use a vacuum defoaming machine to perform defoaming treatment on the slurry for 40 minutes, and then cast the defoamed slurry into a film through a casting machine with a knife adjustment of 200 and a casting rate of 20cm/min , after drying at room temperature for 4 hours, a La _0.7 Sr _0.3 MnO ₃ thick film can be obtained.

Example 5

This embodiment provides a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film, wherein the preparation method of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film is as follows:

S1: Preparation of La _0.7 Sr _0.3 MnO ₃ powder.

S2: Preparation of La _0.7 Sr _0.3 MnO ₃ thick film.

According to an example of the present invention, the specific operation of S1 is as follows:

S101: According to their general chemical formula, weigh lanthanum oxide (99.99%), strontium carbonate (99%), manganese dioxide (99.8%), barium titanate (99%), titanium dioxide powder (100%) respectively, weigh After it is ready, put it in the ball mill pot according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1, set the speed of the planetary ball mill to 400rpm, and the ball milling time is 24h. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S102: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C.

S103: Pre-fire the dried mixed powder, put it in an alumina crucible, then put it in a tube furnace, supply oxygen, set the temperature from room temperature to 1050°C, keep it warm for 4 hours, and the heating rate is 3°C /min, the cooling rate is 5°C/min, when the temperature drops to 500°C, it will be cooled to room temperature with the furnace.

S104: Take out the pre-burned La _0.7 Sr _0.3 MnO ₃ powder, crush it with an agate mortar, and place it in a ball mill jar according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1 . The rotation speed of the planetary ball mill is set to 400 rpm, and the ball milling time is 24 hours. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S105: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C. After drying, dry La _0.7 Sr _0.3 MnO ₃ powder can be obtained.

According to an example of the present invention, the specific operation of S2 is as follows:

S201: Mix the dried powder with the organic solvent toluene-ethanol and the dispersant triolein, add zirconia balls, and put them into a three-dimensional powder mixer to mix the powder, wherein, the powder mass: zirconia ball mass: Solvent mass: dispersant mass = 18:27:25:2. The powder mixing time is 240min, and the preliminary slurry is obtained

S202: Add polyethylene glycol, phthalate diester and polyvinyl butylate to the preliminary slurry, wherein the mass ratio is, original powder: polyethylene glycol: phthalate diester: polyethylene Butyl alcohol = 18:10:3:5. Then mix the powder for 360 minutes to get the final slurry.

S203: Use a vacuum defoaming machine to perform defoaming treatment on the slurry for 40 minutes, and then cast the defoamed slurry into a film through a casting machine with a knife adjustment of 200 and a casting rate of 20cm/min , after drying at room temperature for 4 hours, a La _0.7 Sr _0.3 MnO ₃ thick film can be obtained.

Comparative example 1

This embodiment provides a ferromagnetic metal oxide La _0.5 Sr _0.5 MnO ₃ thick film, wherein, the preparation method of the ferromagnetic metal oxide La _0.5 Sr _0.5 MnO ₃ thick film is as follows:

S1: Preparation of La _0.5 Sr _0.5 MnO ₃ powder.

S2: Preparation of La _0.5 Sr _0.5 MnO ₃ thick film.

According to an example of the present invention, the specific operation of S1 is as follows:

S101: According to their general chemical formula, weigh lanthanum oxide (99.99%), strontium carbonate (99%), manganese dioxide (99.8%), barium titanate (99%), titanium dioxide powder (100%) respectively, weigh After it is ready, put it in the ball mill pot according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1, set the speed of the planetary ball mill to 400rpm, and the ball milling time is 24h. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S102: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C.

S103: Pre-fire the dried mixed powder, put it in an alumina crucible, then put it in a tube furnace, supply oxygen, set the temperature from room temperature to 850°C, keep it warm for 4 hours, and the heating rate is 3°C /min, the cooling rate is 5°C/min, when the temperature drops to 500°C, it will be cooled to room temperature with the furnace.

S104: Take out the pre-burned La _0.5 Sr _0.5 MnO ₃ powder, crush it with an agate mortar, and place it in a ball mill jar according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1 . The rotation speed of the planetary ball mill is set to 400 rpm, and the ball milling time is 24 hours. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S105: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C. After drying, dry La _0.5 Sr _0.5 MnO ₃ powder can be obtained.

According to an example of the present invention, the specific operation of S2 is as follows:

S201: Mix the dried powder with the organic solvent toluene-ethanol and the dispersant triolein, add zirconia balls, and put them into a three-dimensional powder mixer to mix the powder, wherein, the powder mass: zirconia ball mass: Solvent mass: dispersant mass = 18:27:25:2. The powder mixing time is 240min, and the preliminary slurry is obtained

S202: Add polyethylene glycol, phthalate diester and polyvinyl butylate to the preliminary slurry, wherein the mass ratio is, original powder: polyethylene glycol: phthalate diester: polyethylene Butyl alcohol = 18:10:3:5. Then mix the powder for 360 minutes to get the final slurry.

S203: Use a vacuum defoaming machine to perform defoaming treatment on the slurry for 40 minutes, and then cast the defoamed slurry into a film through a casting machine with a knife adjustment of 200 and a casting rate of 20cm/min , La _0.5 Sr _0.5 MnO ₃ thick film can be obtained after drying for 4h.

Comparative example 2

This embodiment provides a flexible ferromagnetic metal oxide La _0.2 Sr _0.8 MnO ₃ thick film, wherein the preparation method of the ferromagnetic metal oxide La _0.2 Sr _0.8 MnO ₃ thick film is as follows:

S1: Preparation of La _0.2 Sr _0.8 MnO ₃ powder.

S2: Preparation of La _0.2 Sr _0.8 MnO ₃ thick film.

According to an example of the present invention, the specific operation of S1 is as follows:

S101: According to their general chemical formula, weigh lanthanum oxide (99.99%), strontium carbonate (99%), manganese dioxide (99.8%), barium titanate (99%), titanium dioxide powder (100%) respectively, weigh After it is ready, put it in the ball mill pot according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1, set the speed of the planetary ball mill to 400rpm, and the ball milling time is 24h. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S102: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C.

S103: Pre-fire the dried mixed powder, put it in an alumina crucible, then put it in a tube furnace, supply oxygen, set the temperature from room temperature to 850°C, keep it warm for 4 hours, and the heating rate is 3°C /min, the cooling rate is 5°C/min, when the temperature drops to 500°C, it will be cooled to room temperature with the furnace.

S104: Take out the pre-burned La _0.2 Sr _0.8 MnO ₃ powder, crush it with an agate mortar, and place it in a ball mill jar according to the mass ratio of powder: ball milling medium (agate ball): alcohol = 1:1.5:1 . The rotation speed of the planetary ball mill is set to 400 rpm, and the ball milling time is 24 hours. Wherein, the diameter of the used agate ball is 2-10mm, and the size varies.

S105: After the balls are milled, take them out and place them in an oven to dry for 9 hours at a drying temperature of 80°C. After drying, dry La _0.2 Sr _0.8 MnO ₃ powder can be obtained.

According to an example of the present invention, the specific operation of S2 is as follows:

S201: Mix the dried powder with the organic solvent toluene-ethanol and the dispersant triolein, add zirconia balls, and put them into a three-dimensional powder mixer to mix the powder, wherein, the powder mass: zirconia ball mass: Solvent mass: dispersant mass = 18:27:25:2. The powder mixing time is 240min, and the preliminary slurry is obtained

S202: Add polyethylene glycol, phthalate diester and polyvinyl butylate to the preliminary slurry, wherein the mass ratio is, original powder: polyethylene glycol: phthalate diester: polyethylene Butyl alcohol = 18:10:3:5. Then mix the powder for 360 minutes to get the final slurry.

S203: Use a vacuum defoaming machine to perform defoaming treatment on the slurry for 40 minutes, and then cast the defoamed slurry into a film through a casting machine with a knife adjustment of 200 and a casting rate of 20cm/min , La _0.2 Sr _0.8 MnO ₃ thick film can be obtained after drying for 12h.

Comparative example 3

This comparative example provides a kind of ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ ceramics, wherein, the preparation method of ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ ceramics is as follows:

S1: Cut the La _0.7 Sr _0.3 MnO ₃ thick film prepared in the above example 1 into a size of 5*5mm, which is characterized in that the substrate is a zirconia plate, and the film can be pressed on the substrate by hot pressing, The pressure is 80MPa, the time is 40min, and the temperature is 65°C.

S2: Put the pressed film in a tube furnace, pass oxygen, and keep warm at 600°C for 300min, with a heating rate of 3°C/min and a cooling rate of 5°C/min.

S3: Sinter the film with glue discharged in the tube furnace under the condition of oxygen flow, set from room temperature to 1200°C, the heating rate is 3°C/min, the holding time is 500min, and the cooling rate is 5°C/min , and when it drops to 500°C, it is cooled to room temperature with the furnace. That is, a flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ ceramic sheet is obtained.

Fig. 1 is the XRD pattern of flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film under different calcining temperatures, as can be seen from Fig. 1, the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film prepared by the present invention It is a perovskite oxide and has no obvious impurities.

Figure 2 is the SEM image of the thick film of the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ at different pre-firing temperatures and the comparative La _0.7 Sr _0.3 MnO ₃ ceramic sheet. It can be seen from Figure 2 that the flexible ferromagnetic metal oxide When the La _0.7 Sr _0.3 MnO ₃ thick film is continuously increased in the calcining temperature, the particles are arranged more and more closely, and the compactness is good. The morphology is the best at 850 °C, and then as the temperature increases, pores appear in the sample and the compactness becomes poor. The SEM of La _0.7 Sr _0.3 MnO ₃ ceramics is formed by thick film sintering at 850 °C pre-fired. It can be seen that the compactness of the ceramic sheet is good, which also shows that the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film prepared by the present invention has good processability and good plasticity.

Figure 3(a)～(e) are the energy spectra of the thick film of flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ at different pre-firing temperatures and the comparative example La _0.7 Sr _0.3 MnO ₃ ceramic sheet in Figure 3(f) Both are undistorted, which means the data is reliable.

As shown in Fig. 4 and Fig. 5, the flexible ferromagnetic metal oxide LSMO thick film prepared by the present invention has good ferromagnetism, and its stability is good in a wide temperature range. At the same time, it can be seen that it exhibits an obvious hysteresis curve at room temperature. Comparing the LSMO thick films with different components in Example 1 and 2, it can be clearly seen that the hysteresis curve of the thick film prepared in Example 3 has better ferromagnetism than that of Comparative Examples 1 and 2, while The ceramic prepared in Example 3 also exhibits good ferromagnetism. From another aspect, it also shows that the ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film prepared by the present invention has strong processability and certain flexibility. It can be seen from Figure 5 that Example 3 has a higher Curie temperature, which shows that the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film prepared by the present invention has better ferromagnetism, and also reflects the present invention. The flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ thick film has a good research prospect, which provides a new idea for the preparation and research of ferromagnetic materials.

The above descriptions are only preferred embodiments of the present invention, and are only illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims (10)

1. The flexible transition metal oxide lanthanum strontium manganese oxygen ferromagnetism thick film is characterized in that the chemical general formula of the flexible transition metal oxide lanthanum strontium manganese oxygen ferromagnetism thick film is La _0.7 Sr _0.3 MnO ₃ 。

2. The flexible transition metal oxide lanthanum strontium manganese oxygen ferromagnetic thick film of claim 1, wherein the thickness of the flexible transition ferromagnetic thick film is 10-20 μ ι η.

3. A method for preparing a flexible thick film of transition metal oxide lanthanum strontium manganese oxygen ferromagnetism as claimed in claim 1 or 2, characterized by comprising the following steps:

s1, lanthanum oxide, strontium carbonate and manganese oxide are mixed according to the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ Weighing a chemical formula of the thick film, mixing the mixed powder, a ball milling medium and alcohol, and performing ball milling;

s2, drying the ball-milled powder obtained in the step S1, pre-burning and preserving heat the dried powder, grinding the powder, and drying to obtain the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ Powder;

s3, mixing the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ Fully and uniformly mixing the powder with an organic solvent to obtain the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ A thick film paste;

s4, removing bubbles from the slurry obtained in the step S3, then casting the slurry into a film, and drying to obtain the flexible ferromagnetic metal oxide La _0.7 Sr _0.3 MnO ₃ And (4) thick film.

4. The method according to claim 3, wherein the ball-milling medium in step S1 is agate balls, and the diameter of the agate balls is 2-10 mm.

5. The method for preparing a flexible thick film of transition metal oxide lanthanum strontium manganese oxygen ferromagnetism according to claim 3, wherein during ball milling in the step S1, the mass ratio of the mixed powder, the ball milling medium and the alcohol is 1.5.

6. The method according to claim 3, wherein the drying temperature in step S2 is 60-100 ℃ and the drying time is 6-12 h.

7. The method according to claim 3, wherein the pre-sintering temperature in step S2 is 650-1050 ℃, the holding time is 2-8 h, the ball milling time is 24h, and the drying time is 6-12 h.

8. The method according to claim 3, wherein in step S3, the flexible thick film of lanthanum strontium manganese oxygen ferromagnetic is first prepared by _0.7 Sr _0.3 MnO ₃ Mixing the powder with an organic solvent, a dispersing agent and zirconia balls, uniformly mixing for 200-300 min to obtain a primary slurry, then mixing with a binder and a homogenizing agent, and uniformly mixing for 200-300 min to obtain a final slurry, wherein the organic solvent is toluene-ethanol, the dispersing agent is triolein, the binder is polyethylene glycol, and the homogenizing agent is butyl phthalate.

9. The method according to claim 3, wherein the defoaming in step S4 is performed by a vacuum defoaming machine for 25-60 min.

10. Use of a flexible thick film of transition metal oxide lanthanum strontium manganese oxygen ferromagnetism as defined in claim 1 or 2 in a semiconductor device.

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