CN110172734B - Cubic phase doped cerium ferrite magneto-optical material and preparation method and application thereof - Google Patents

Abstract

The invention provides a cubic phase doped cerium ferrite magneto-optical material and a preparation method and application thereof. The magneto-optical material has a chemical formula of Ce _x1‑Sr _x Fe _x1‑V _x O₃，xAnd =0.3 to 0.7. The material belongs to a cubic crystal system and has a space group. The material has the advantages of novel structure, excellent optical and magnetic properties and remarkable magneto-optical effect, and the lattice constant of the compound is matched with silicon, so that the material is expected to be applied to the fields of silicon-based integrated optoisolators and the like. The material is prepared by a radio frequency magnetron sputtering method, so the material also has the advantages of simple process, short period and good reproducibility.

Description

Cubic phase doped cerium ferrite magneto-optical material and preparation method and application thereof

Technical Field

The invention belongs to the technical field of magneto-optical materials, and particularly relates to a cubic phase doped cerium ferrite magneto-optical material as well as a preparation method and application thereof.

Background

The silicon material has the advantages of low cost, large size, good waveguide property, excellent light guide performance, radiation resistance and the like, so that the silicon material is widely applied to the research and development of photon integrators, photoelectric hybrid integrators and the like, and is one of the important development directions of high-speed informatization in the modern times. In the current development of non-reciprocal photonic integrated devices, cerium-doped yttrium iron garnet (Ce: YIG) having a large faraday rotation angle and low optical loss in the near infrared wavelength region is most studied. Both Lei Bi et al and Xue Yin Sun et al successfully realized monolithically integrated opto-isolators by fabricating Ce: YIG/YIG cladding layers On SOI (Silicon-On-Insulator, Silicon On Insulator), drawing a great deal of attention. However, CeO is easily generated in the preparation process of the material₂And iron oxide, the magneto-optical properties are affected. Furthermore, due to the coefficient of thermal expansion between the garnet film and the Si substrate (YIG: 10.4X 10)^-6K^-1，Si：3×10^-6K^-1) And unit cell parameters (YIG: 12.376A, Si: 5.431A), a garnet-type magneto-optical thin film grown directly on a silicon single crystal plate is prone to cracking.

Perovskite type rare earth ferrite (RFeO)₃R = rare earth element) crystals and films are also one of the important research objects of current magneto-optical materials. The material has the advantages of high sensitivity, high response speed, high magneto-optical figure of merit, high Curie temperature (620-. Compared with garnet materials, the perovskite crystal lattice of the rare earth ferrite has higher matching degree with a silicon substrate, and a high-quality silicon-based magneto-optical film is expected to be prepared. In view of the magnetic ion Ce³⁺Having an enhanced magneto-optical effect, CeFeO₃The film will theoretically have better and superior overall magneto-optical properties. But due to Ce³⁺Unstable and easily oxidized to non-magnetic Ce⁴⁺So pure phase CeFeO₃The preparation of thin films is very difficult. And due to RFeO₃The crystal belongs to an orthorhombic system with low symmetry, the birefringence effect existing in the crystal can greatly reduce the Faraday rotation efficiency, and the crystal is not suitable for the specific application of materials in the aspect of magneto-optic. Relevant research results show that the perovskite compound can regulate the crystal structure by doping appropriate ions into the A, B lattice site. Therefore, it is hopeful to make RFeO by finding suitable ion doping₃The structure is changed to cubic phase, so that the birefringence effect is eliminated and the magneto-optical performance is improved. However, CeFeO is currently doped for cubic phase₃The research on the crystal and the film is not reported in the literature.

This patent is based on the discovery that CeFeO₃The A site is doped with Sr with larger radius and the B site is doped with V with smaller radius, thereby realizing CeFeO for the first time₃The evolution from orthorhombic to cubic. Prepared by adopting a magnetron sputtering method and has<111>Oriented Ce _x1-Sr _x Fe _x1-V _x O₃[ solution of ] Si and Ce _x1-Sr _x Fe _x1-V _x O₃/SrTiO₃ (x=0.3 to 0.7) epitaxial thin film. Magnetic Circular Dichroism (MCD) spectrum, XPS spectrum, ultraviolet-visible spectrum, hysteresis loop, color spectrum,the test structure of the surface appearance and the like shows that the prepared cubic phase doped CeFeO₃The magneto-optical material has high film-forming quality, good optical transmission performance and magnetism, and is expected to provide a novel high-quality magneto-optical film material for developing novel silicon-based magneto-optical devices.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a cubic phase doped cerium ferrite magneto-optical material and a preparation method and application thereof. The magneto-optical material belongs to a cubic crystal system, has a space group, has high lattice adaptability with silicon, is easy to epitaxially grow on a silicon substrate to obtain a high-quality film, has the characteristics of excellent physicochemical performance and excellent magneto-optical effect at room temperature, and has good application prospect in the field of silicon-based integrated optoisolators. The preparation method of the magneto-optical film material has the advantages of simple process, rapidness, short period and good reproducibility.

In order to achieve the purpose, the invention adopts the following technical scheme:

a cubic phase doped cerium ferrite magneto-optical material with a chemical general formula of Ce _x1-Sr _x Fe _x1-V _x O₃， x= 0.3-0.7; belonging to cubic system, and the space group is that the unit cell constant a = b = c = 7.796-7.724A; the rare-earth ferrite is a novel double perovskite rare-earth ferrite structure, wherein Ce and Sr jointly occupy an A lattice site, and Fe and V jointly occupy a B lattice site.

A preparation method of a cubic phase doped cerium ferrite magneto-optical material comprises the following specific steps:

(1) preparing a polycrystalline raw material: according to Ce _x1-Sr _x Fe _x1-V _x O₃，x= 0.3-0.7, and CeO is accurately weighed according to the stoichiometric ratio₂、Fe₂O₃、Fe、SrCO₃、V₂O₅The raw materials are put into a corundum mortar for full grinding, are uniformly mixed and then are pressed into tablets under 30Mpa, and are sintered for 12 hours under vacuum at 850 ℃ by a tube furnace; repeating the grinding, tabletting and sintering operations for one time; in order to ensure that the density of the pressed polycrystalline raw material target is higher, 5mL PVA is added as a bonding agent during the second grinding;

(2) preparing a film: using radio frequency magnetron sputtering method to form (111) -oriented monocrystalline silicon wafer or SrTiO₃Preparation of Ce by using crystal as substrate and Ar as working gas _x1-Sr _x Fe _x1-V _x O₃，x= 0.3-0.7 film;

(3) crystallization treatment: since the sputtered film is amorphous, it is subsequently crystallized, considering Ce³⁺Easily oxidized to non-magnetic Ce⁴⁺And annealing the film for the first time in an inert mixed atmosphere, and placing a plurality of carbon rods in a furnace. To avoid Fe generation under reducing atmosphere²⁺Oxygen vacancy defect affects optical and magnetic properties of the film, and the film needs to be annealed for the second time to obtain Ce _x1-Sr _x Fe _x1-V _x O₃，xAnd (5) 0.3-0.7 magneto-optical material.

The preparation process parameters of the radio frequency magnetron sputtering of the film in the step (2) are as follows: target base distance 5cm, background vacuum 1X 10^-4Pa, Ar as working gas, 1.9Pa of working gas pressure, 20Sccm of gas flow, 80W of sputtering power and 1.5-3 hours of sputtering duration.

In the step (3), the inert mixed atmosphere for the first annealing is 5% H₂With 95% Ar₂The annealing temperature of the first annealing is 650 ℃, the annealing constant-temperature duration is 2 hours, and the heating and cooling rates are 1 ℃/min; the annealing temperature of the second annealing is 500 ℃, the constant temperature is kept for 1 hour in the air atmosphere, and the heating and cooling rates are 1 ℃/min.

The cubic phase doped cerium ferrite magneto-optical material is applied to a silicon-based optical isolator, an optical circulator or a magneto-optical modulator.

The invention has the following remarkable advantages:

(1) the cubic phase doped cerium ferrite magneto-optical material Ce of the invention _x1-Sr _x Fe _x1-V _x O₃，xAnd the (= 0.3-0.7) is a novel magneto-optical material, belongs to a cubic crystal system, and comprises a space group. The lattice mismatch degree of the magneto-optical material and the silicon substrate is small, and the crystallization partThe obtained film has obvious (111) plane preferred orientation, good film forming quality and root mean square roughness (Rq) below 10 nm.

(2) The magneto-optical material has good optical transmission performance, strong saturation magnetization intensity and strong magneto-optical performance. When the Ce content of the A site is 70%, the magnetic circular dichroism response value (MCD) reaches-4300 deg./cm (external magnetic field is 2500Oe), which indicates that the material has excellent magneto-optical performance and is expected to be applied to the field of silicon-based photoelectric integrated devices.

(3) The preparation method of the invention has simple and rapid process, short period and good reproducibility.

Drawings

FIG. 1 is Ce sputtered for 1.5 hours _x1-Sr _x Fe _x1-V _x O₃X-ray diffraction (XRD) spectrum of the/Si (111) thin film after annealing. Silicon Substrate: a silicon substrate; JCPDS 54-0757: perovskite cubic phase standard card.

FIG. 2 is Ce of different thicknesses _x1-Sr _x Fe _x1-V _x O₃Grazing incidence spectrum diffraction (GIXRD) spectrum after annealing of the/Si (111) thin film (ω = 1 °). (a) Sputtering for 1.5 hours; (b) sputtering for 3 hours; JCPDS 54-0757: perovskite cubic phase standard card.

FIG. 3 is Ce _x1-Sr _x Fe _x1-V _x O₃AFM 2D plot of/Si (111) thin film. (a) Ce_0.3Sr_0.7Fe_0.3V_0.7O₃, (b) Ce_0.5Sr_0.5Fe_0.5V_0.5O₃, (c) Ce_0.7Sr_0.3Fe_0.7V_0.3O₃。

FIG. 4 is Ce _x1-Sr _x Fe _x1-V _x O₃Transmission spectrum of the/Si (111) thin film. Si (111) Substrate: a silicon substrate.

FIG. 5 is Ce _x1-Sr _x Fe _x1-V _x O₃Of a/Si (111) filmRoom temperature saturation hysteresis spectrum (out-of-plane).

FIG. 6 is Ce _x1-Sr _x Fe _x1-V _x O₃Ce 3d XPS spectra of/Si (111) thin films.

FIG. 7 is Ce _x1-Sr _x Fe _x1-V _x O₃/SrTiO₃(111) MCD spectra of the films.

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.

Example 1

Cubic phase doped cerium ferrite magneto-optical material Ce_0.7Sr_0.3Fe_0.7V_0.3O₃The preparation method comprises the following specific steps:

(1) preparing a polycrystalline raw material: according to Ce_0.7Sr_0.3Fe_0.7V_0.3O₃Accurately weighing CeO in stoichiometric ratio₂、Fe₂O₃、Fe、SrCO₃、V₂O₅Placing in a corundum mortar, fully grinding and uniformly mixing, pressing into tablets under 30Mpa, and presintering for 12 hours at 850 ℃ in a vacuum atmosphere by using a tube furnace; repeating the grinding, tabletting and sintering operations for one time; in the process of preparing the polycrystalline raw material target, 5mL of PVA is added as a bonding agent during the second grinding in order to ensure that the compacted target has higher compactness.

(2) Preparing a film: adopting radio frequency magnetron sputtering method to respectively use (111) oriented monocrystalline silicon slice and SrTiO₃The wafer is used as a substrate to prepare Ce_0.7Sr_0.3Fe_0.7V_0.3O₃[ Si (111) film and Ce_0.7Sr_0.3Fe_0.7V_0.3O₃/SrTiO₃(111) A film. The technological parameters of magnetron sputtering are as follows: target base distance 5cm, background vacuum 1X 10^-4Pa, Ar as working gas, 1.9Pa of working gas pressure, 20Sccm of gas flow, 80W of sputtering power, sputteringThe duration is 1.5 hours and 3 hours, and Ce with different thicknesses is prepared_0.7Sr_0.3Fe_0.7V_0.3O₃[ Si (111) film and Ce_0.7Sr_0.3Fe_0.7V_0.3O₃/SrTiO₃(111) A film.

(3) Crystallization treatment: since the sputtered film is amorphous, it is subsequently crystallized, considering Ce³⁺Easily oxidized to non-magnetic Ce⁴⁺The film is annealed for the first time in an inert mixed atmosphere, and 5% H is introduced into the vacuum tube furnace₂With 95% Ar₂Placing a plurality of carbon rods in the furnace for annealing, wherein the annealing temperature is 650 ℃, the constant temperature duration is 2 hours, and the heating and cooling rates are both 1 ℃/min. In addition, to avoid Fe generation under a reducing atmosphere²⁺The film performance is influenced, the temperature is kept constant for 1 hour at 500 ℃ under the air atmosphere, and the secondary annealing is carried out at the temperature rising and reducing speed of 1 ℃/min.

For the crystallized Ce_0.7Sr_0.3Fe_0.7V_0.3O₃The phase of the/Si (111) film is characterized, and an X-ray diffraction (XRD) spectrum (see figure 1) shows that the diffraction peak of the film only appears on the (111) surface except the diffraction peak of the substrate, which indicates that the film has<111>Preferred orientation. In order to reduce the influence of the substrate on the thin film phase analysis, grazing incidence small angle diffraction (GIXRD) test (ω = 1 °) was performed, and the results are shown in fig. 2. GIXRD spectrum shows Ce obtained on Si (111) substrate_0.7Sr_0.3Fe_0.7V_0.3O₃the/Si (111) film phase conforms to the perovskite cubic phase standard card (JCPDS 54-0757), except that SiO resulting from oxidation of the silicon substrate occurs at the 28.46 ℃ position₂Otherwise, no other miscellaneous phase is generated. And appear in XRD spectra<111>The orientation peak is close to the peak of the Si substrate, and therefore does not appear in the grazing incidence diffraction spectrum. The GIXRD spectrum of the film is subjected to Rietveld refinement, and the result shows that Ce_0.7Sr_0.3Fe_0.7V_0.3O₃The perovskite cubic structure is represented by/Si (111), and the unit cell constant a = b = c =7.796 a. FIG. 3c is Ce_0.7Sr_0.3Fe_0.7V_0.3O₃AFM surface topography of/Si (111) thin films. The result shows that the surface particles of the film after crystallization treatment are uniformly distributed and have no cracks, and the root mean square roughness of the surface is 10 nm. Further, as is clear from the transmission spectrum of FIG. 4, 1.5 hours of Ce was sputtered_0.7Sr_0.3Fe_0.7V_0.3O₃the/Si (111) film has a transmittance of 55 to 65%. The film has an improved transmittance compared to the substrate. The film has high quality and lower refractive index than monocrystalline silicon, and has anti-reflection effect on the substrate. FIG. 5 is Ce _x1-Sr _x Fe _x1-V _x O₃Room temperature saturation hysteresis (out-of-plane) spectra of the/Si (111) film. As shown in FIG. 5, Ce_0.7Sr_0.3Fe_0.7V_0.3O₃The saturation magnetization of the/Si (111) film was 50emu/cm³The coercive force was 112 Oe. The valence state of Ce ions in the film was analyzed by photoelectron spectroscopy XPS (see fig. 6). As is clear from FIG. 6, Ce of the present example_0.7Sr_0.3Fe_0.7V_0.3O₃The valence state of Ce ions in the/Si (111) film is all +3, and non-magnetic Ce is not used⁴⁺Production of (Ce)⁴⁺Characteristic peak position at 916.9 eV). FIG. 7 is Ce_0.7Sr_0.3Fe_0.7V_0.3O₃/SrTiO₃(111) MCD spectrum of the film in 380-800 nm wave band (external magnetic field is 2500 Oe). As shown in FIG. 7, Ce_0.7Sr_0.3Fe_0.7V_0.3O₃/SrTiO₃(111) The magneto-circular dichroism response value of the film at a wavelength of 562 nm reaches-4300 deg./cm. Under the same magnetic field, the magneto-optical performance of the film is far higher than that of garnet type Ce-containing film reported in the literature³⁺Magneto-optical film^[1]。

Example 2

Cubic phase doped cerium ferrite magneto-optical material Ce_0.5Sr_0.5Fe_0.5V_0.5O₃The preparation method comprises the following specific steps:

(1) preparing a polycrystalline raw material: accurately weighing CeO according to stoichiometric ratio₂、Fe₂O₃、Fe、SrCO₃、V₂O₅Is arranged in a corundum grinderFully grinding and uniformly mixing the materials in a bowl, pressing the materials into tablets under 30Mpa, and presintering the tablets for 12 hours at 850 ℃ in a vacuum atmosphere by using a tube furnace; repeating the grinding, tabletting and sintering operations for one time; in the process of preparing the polycrystalline raw material target, 5mL of PVA is added as a bonding agent during the second grinding in order to ensure that the compacted target has higher compactness.

(2) Preparing a film: adopting radio frequency magnetron sputtering method to respectively use (111) oriented monocrystalline silicon slice and SrTiO₃The wafer is used as a substrate to prepare Ce_0.5Sr_0.5Fe_0.5V_0.5O₃[ Si (111) film and Ce_0.5Sr_0.5Fe_0.5V_0.5O₃/SrTiO₃(111) A film. The technological parameters of the sputtering control are as follows: target base distance 5cm, background vacuum 1X 10^-4Pa, Ar as working gas, 1.9Pa of working gas pressure, 20Sccm of gas flow, 80W of sputtering power, 1.5 hours and 3 hours of sputtering duration, and preparing Ce with different thicknesses_0.5Sr_0.5Fe_0.5V_0.5O₃[ Si (111) film and Ce_0.5Sr_0.5Fe_0.5V_0.5O₃/SrTiO₃(111) A film.

(3) Crystallization treatment: since the sputtered film is amorphous, it is subsequently crystallized, considering Ce³⁺Easily oxidized to non-magnetic Ce⁴⁺Annealing the film for the first time in an inert mixed atmosphere, and introducing H into the film in a vacuum tube furnace₂And Ar₂Mixing the gases, and placing a plurality of carbon rods in the furnace for annealing. The annealing temperature is 650 ℃, the constant temperature duration is 2 hours, and the temperature rise and fall rates are both 1 ℃/min. In addition, to avoid Fe generation under a reducing atmosphere²⁺The film performance is influenced, and the secondary annealing is carried out at the constant temperature of 500 ℃ for 1 hour under the air atmosphere and at the temperature rising and reducing rates of 1 ℃/min.

For the crystallized Ce_0.5Sr_0.5Fe_0.5V_0.5O₃The phase of the/Si (111) film is characterized, and the diffraction peak of the film only appears on the (111) plane except the diffraction peak of the substrate from the XRD spectrum (see figure 1), which indicates that the film has<111>Preferred orientation. The GIXRD spectrum of FIG. 2 shows Ce_0.5Sr_0.5Fe_0.5V_0.5O₃the/Si (111) film phase conforms to the perovskite cubic phase standard card (JCPDS 54-0757). And appear in XRD spectra<111>The orientation peak is close to the peak of the Si substrate and therefore does not appear in the grazing incidence diffraction spectrum. The Rietveld refinement result shows that Ce_0.5Sr_0.5Fe_0.5V_0.5O₃The perovskite cubic structure is represented by/Si (111), and the unit cell constant a = b = c =7.766 a. FIG. 3b is a 2D graph of the AFM surface topography of the thin film of this example. The result shows that the grain distribution on the surface of the crystallization processing film is uniform and has no crack, and the root mean square roughness of the film sputtered for 1.5 hours is 9.50 nm. Further, as is clear from the transmission spectrum of fig. 4, the transmittance of the film was as high as 70%, which is significantly higher than that of the substrate. FIG. 5 is Ce_{1- x} Sr _x Fe _x1-V _x O₃Room temperature saturation hysteresis (out-of-plane) spectra of the/Si (111) film. As shown in FIG. 5, Ce_0.5Sr_0.5Fe_0.5V_0.5O₃The saturation magnetization of the/Si (111) film was 37.5emu/cm³The coercive force was 253 Oe. XPS spectrum of FIG. 6 shows Ce of the present case_0.5Sr_0.5Fe_0.5V_0.5O₃The valence state of Ce ions in the/Si (111) film is all +3, and non-magnetic Ce is not used⁴⁺And (4) generating. Ce_0.5Sr_0.5Fe_0.5V_0.5O₃/SrTiO₃(111) The MCD value of the film at the wavelength of 466 nm reaches-2700 deg./cm (the external magnetic field is 2500Oe) (see figure 7), and the film also has the strong magnetic-optical effect.

Example 3

Cubic phase doped cerium ferrite magneto-optical material Ce_0.3Sr_0.7Fe_0.3V_0.7O₃The preparation method comprises the following specific steps:

(1) preparing a polycrystalline raw material: accurately weighing CeO according to stoichiometric ratio₂、Fe₂O₃、Fe、SrCO₃、V₂O₅Placing in corundum mortar, grinding, mixing, and pressing under 30MpaPre-sintering the wafer for 12 hours at 850 ℃ in a vacuum atmosphere by using a tube furnace; repeating the grinding, tabletting and sintering operations for one time; in the process of preparing the polycrystalline raw material target, 5mL of PVA is added as a bonding agent during the second grinding in order to ensure that the compacted target has higher compactness.

(2) Preparing a film: adopting radio frequency magnetron sputtering method to respectively use (111) oriented monocrystalline silicon slice and SrTiO₃The wafer is used as a substrate to prepare Ce_0.3Sr_0.7Fe_0.3V_0.7O₃[ Si (111) film and Ce_0.3Sr_0.7Fe_0.3V_0.7O₃/SrTiO₃(111) A film. The technological parameters of the sputtering control are as follows: target base distance 5cm, background vacuum 1X 10^-4Pa, Ar as working gas, 1.9Pa of working gas pressure, 20Sccm of gas flow, 80W of sputtering power, 1.5 hours and 3 hours of sputtering duration, and preparing Ce with different thicknesses_0.3Sr_0.7Fe_0.3V_0.7O₃[ Si (111) film and Ce_0.3Sr_0.7Fe_0.3V_0.7O₃/SrTiO₃(111) A film.

(3) Crystallization treatment: since the sputtered film is amorphous, it is subsequently crystallized, considering Ce³⁺Easily oxidized to non-magnetic Ce⁴⁺Annealing the film for the first time in an inert mixed atmosphere, and introducing H into the film in a vacuum tube furnace₂And Ar₂Mixing the gases, and placing a plurality of carbon rods in the furnace for annealing. The annealing temperature is 650 ℃, the constant temperature duration is 2 hours, and the heating and cooling rates are both 1 ℃/min. In addition, to avoid Fe generation under a reducing atmosphere²⁺The film performance is influenced, and the secondary annealing is carried out at the constant temperature of 500 ℃ for 1 hour under the air atmosphere and at the temperature rising and reducing rates of 1 ℃/min.

For the crystallized Ce_0.3Sr_0.7Fe_0.3V_0.7O₃The phase of the/Si (111) film is characterized, and the XRD spectrum (see figure 1) shows that only the diffraction peak of the film on the (111) surface of the Si (111) substrate is shown besides the diffraction peak of the substrate, which indicates that the film has<111>Preferred orientation. GIXRD spectrum shows that at SCe obtained on i (111) substrate_0.3Sr_0.7Fe_0.3V_0.7O₃the/Si (111) film phase conforms to the perovskite cubic phase standard card (JCPDS 54-0757). The Rietveld finishing results of the film show that Ce_0.3Sr_0.7Fe_0.3V_0.7O₃The perovskite cubic structure is represented by/Si (111), and the unit cell constant a = b = c =7.724 a. FIG. 3a is a 2D plot of the AFM surface topography of the film. The result shows that the surface particles of the film after crystallization treatment are uniformly distributed and have no cracks, and the root mean square roughness is 8.71 nm. From the transmission spectrum of FIG. 4, Ce was sputtered for 1.5 hours_0.3Sr_0.7Fe_0.3V_0.7O₃The maximum transmittance of the/Si (111) film can reach 65 percent and is obviously higher than that of a silicon substrate. FIG. 5 is Ce _x1-Sr _x Fe _x1-V _x O₃Room temperature saturation hysteresis (out-of-plane) spectra of the/Si (111) film. As shown in FIG. 5, Ce_0.3Sr_0.7Fe_0.3V_0.7O₃The saturation magnetization of the/Si (111) film was 19emu/cm³Lower than Ce_0.5Sr_0.5Fe_0.5V_0.5O₃[ solution ]/Si (111) and Ce_0.7Sr_0.3Fe_0.7V_0.3O₃Si (111), but the coercivity can be increased to 356 Oe. The Gaussian fitting results of XPS spectra (see FIG. 6) illustrate the Ce of the present case_0.3Sr_0.7Fe_0.3V_0.7O₃The valence state of Ce ions in the/Si (111) film is all +3, and non-magnetic Ce is not used⁴⁺And (4) generating. Ce_0.3Sr_0.7Fe_0.3V_0.7O₃/SrTiO₃(111) The MCD spectrum (with an applied magnetic field of 2500Oe) (see FIG. 7) of the film at 564 nm wavelength was 1100deg./cm, indicating a strong magneto-optical effect.

The above description is only a preferred embodiment of the present invention, and all changes and modifications made in the spirit of the present invention should be covered by the present invention.

1] M. Kucera, J. Bok and K. Nitsch. Faraday rotation and MCD in Ce Doped YIG. Solid State Commun., 69 [11] 1117-1121 (1989)。

Claims (4)

1. A cubic phase doped cerium ferrite magneto-optical material is characterized in that: the cubic phase doped cerium ferrite magneto-optical material has a chemical formula of Ce _x1-Sr _x Fe _x1-V _x O₃，x=0.5, cubic crystal system, unit cell constant a = b = c =7.766 a, susceptible to epitaxial growth on a silicon substrate; the rare-earth ferrite structure is a double perovskite rare-earth ferrite structure, wherein Ce and Sr jointly occupy an A lattice site, and Fe and V jointly occupy a B lattice site.

2. A method of preparing a cubic phase doped cerium ferrite magneto-optical material as claimed in claim 1, comprising the steps of:

(1) preparing a polycrystalline raw material: according to Ce _x1-Sr _x Fe _x1-V _x O₃，xAccurately weighing CeO in stoichiometric ratio of =0.5₂、Fe₂O₃、Fe、SrCO₃、V₂O₅The raw materials are put into a corundum mortar for full grinding, are uniformly mixed and then are pressed into tablets under 30Mpa, and are sintered for 12 hours under vacuum at 850 ℃ by a tube furnace; repeating the grinding, tabletting and sintering operations for one time; in order to ensure that the density of the pressed polycrystalline raw material target is higher, 5mL PVA is added as a bonding agent during the second grinding;

(2) preparing a film: using radio frequency magnetron sputtering method to form (111) -oriented monocrystalline silicon wafer or SrTiO₃Preparation of Ce by using crystal as substrate and Ar as working gas _x1-Sr _x Fe _x1-V _x O₃，x=0.5 film;

(3) crystallization treatment: carrying out primary annealing on the film prepared in the step (2) in an inert mixed atmosphere, and placing a plurality of carbon rods in a furnace; to avoid Fe generation under reducing atmosphere²⁺Oxygen vacancy defect affects optical and magnetic properties of the film, and the film needs to be annealed for the second time to obtain Ce _x1-Sr _x Fe _x1-V _x O₃，x=0.5 magneto-optical material.

3. The method of claim 2, wherein: the preparation process parameters of the radio frequency magnetron sputtering of the film in the step (2) are as follows: target base distance 5cm, background vacuum 1X 10^-4Pa, Ar as working gas, 1.9Pa of working gas pressure, 20Sccm of gas flow, 80W of sputtering power and 1.5-3 hours of sputtering duration.

4. The method of claim 2, wherein: in the step (3), the inert mixed atmosphere for the first annealing is 5% of H₂With 95% Ar₂The annealing temperature of the first annealing is 650 ℃, the annealing constant-temperature duration is 2 hours, and the heating and cooling rates are 1 ℃/min; the annealing temperature of the second annealing is 500 ℃, the constant temperature is kept for 1 hour in the air atmosphere, and the heating and cooling rates are 1 ℃/min.

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