Growth And Performance Research Of YIG Magneto-optical Crystal

YIG(Y₃Fe₅O₁₂)is a typical rare earth iron garnet magneto-optical crystal material,it has the characteristics of high transmittance,low absorption and high Verdet constant in the near-infrared band.Therefore,it has an excellent core position in the study of magnetic theory and microwave technology.In this paper,co-precipitation method and sol-gel method were adopted to synthetize powders.The powders prepared by two methods referred above were characterized by TG-DSC,XRD,FT-IR,SEM and VSM respectively.After comparative analysis,sol-gel method was confirmed to product polycrystal materials.The YIG crystal was successfully grown by using the flux pulling method with intermediate frequency induction heating,reasonable temperature field designment and appropriate adjustment of technological parameter.The YIG crystal was characterized by X-ray diffraction,transmission,absorption,Raman spectroscopy,magnetic hysteresis loop and Verdet constant.The results show that the YIG single crystal has a narrow peak shape,high intensity,good symmetry and high single crystal rate.In the wavelength range of 1200-3000 nm,the transmittance is up to 88% and the average absorption coefficiency is 3.65cm-1,which indicated the YIG crystal has an excellent transmission,which means that it will satisfy the using and designing requirements.That characteristic peaks of raman scattering spectra are coherent with the vibration peak of YIG crystals,which means the crystals have a high purity.From the magnetic hysteresis loop,we can declare that YIG crystals belongs to typical ferrimagnetic materials.And the fact that the saturation magnetization is 27.2emu/g,which indicates that YIG could be saturated magnetized by exerting a small magnetic field,which could totally satisfy the applying requirements.The Verdet constant of YIG crystals was tested by extinction method,which affirmed that the crystal had high Verdet constant and could be put into practical application.