The Study Of YIG Film Materials Applied In Microwave And Magneto-optic Components

In order to adapt to the development of new optical communication technology and microwave photonic system integration,miniaturization and lightweight,microwave magnetic devices and magneto-optical devices must also be developed in the direction of film miniaturization.The garnet-type ferrite represented by yttrium iron garnet?YIG?can effectively improve the microwave gyromagnetic properties and magneto-optical properties of the material by different ion substitutions,so it is a very important gyromagnetic and magneto-optical functional material.The thinning of this material is an important international research and development direction.This thesis mainly studies the ion-substituted modification of YIG film,film preparation and characterization,and the application of film in microwave and magneto-optical devices.The research content mainly includes the following three aspects:1.Design of magneto-optical and microwave YIG thin film materialsBased on the energy level transition model,theoretically calculate and simulate the magneto-optical Faraday angle spectrum,finding the best formula,the best 12-face position replacement ions,and Tb³⁺,Dy³⁺,Bi³⁺ions instead of Y³+ions to increase the magneto-optical Faraday effect mechanism and law;Study the improvement of saturation magnetization,ferromagnetic resonance linewidth and temperature characteristics of YIG materials for microwave applications leaded by ion replacement,especially the combination of tetrahedral non-magnetic ion substitution and12-faced rare earth ion substitution.And design YIG film formulation with controllable saturation magnetization and good temperature stability and low ferromagnetic resonance line width;Study the melt formulation of liquid phase epitaxy YIG single crystal film growth,including the selection and optimization of cosolvent system,material formulation and material selection,and substrate substrate selection.2.Preparation technology of YIG film?single crystal/polycrystalline film?materiala.Study YIG single crystal thin film liquid phase epitaxy growth process,including the research on the influence on the preparation process of melt formulation,ion substitution,etc.,which is the main method to solve the adjustment of saturation magnetization,the improvement of temperature characteristics,the influence of the increase of magneto-optical Faraday angle.The research of single crystal GGG base choose,the preparation of the buffer layer,the orientation accuracy of the GGG crystal axis and the influence of the epitaxial growth rate on the microstructure of the YIG single crystal epitaxial film defects and surface morphology,especially the factors affecting the thickness of the film to solve the problem of preparation of a"thick"YIG single crystal film of hundreds of microns.At the same time,the relationship between the microstructure of YIG single crystal film,the properties of the film material,the effects of magneto-optical and microwave properties on the material were studied.b.Study the sputtering preparation process of high uniformity YIG polycrystalline thin film material,including sputtering gas pressure,substrate temperature,target-substrate spacing,sputtering beam density,film crystallization annealing process,etc.Which has a significant effect on the match of particle size,film uniformity,lattice constant with the substrate layer,and the control of crystal orientation etc.3.Study on application of YIG film in microwave resonators,including resonant unit design,magnetic field tuning,strength and uniformity of gap field,magnetoelectric coupling mechanism and tuning characteristics of layered magnetoelectric coupling resonator etc.;design and fabrication of magneto-optical isolators based on YIG single crystal thin films,including device structure design,optimization and fabrication,performance testing,etc.