Preparation And Magneto-optical Properties Of Yttrium Stabilized Terbium Oxide(Tb_xY_1-x)₂O₃ Transparent Ceramics

Magneto-optic material is a kind of optical information functional material with magneto-optic effect,which has been widely used in laser,optical fiber communication,computer technology and medical treatment and other high-tech fields.Currently,the most commonly used magneto-optical material is Tb₃Ga₅O₁₂?TGG?single crystal,whose field constant at 633 nm is-134rad/T·m.With the continuous progress of science and technology,magneto-optical isolators and deflectors with magneto-optical materials as the core are gradually developing towards the direction of integration,miniaturization and lightweight.In particular,rare earth sesquioxides exhibit excellent magneto-optical properties,among which terbium oxide?Tb₂O₃?has good magneto-optical isolation performance,and its field constant can be more than 3 times as high as that of commercial TGG single crystal.However,terbium ions can easily change valence in an oxygen-containing atmosphere,and terbium oxide has a serious phase transition at 1600?,so the preparation of terbium oxide transparent ceramics has been rarely reported.In the past two years,Russian and Japanese scholars have used the hot pressing and hot isostatic pressing techniques to sintering yttrium stabilized terbium oxide transparent ceramics,respectively.However,the carburizing of the ceramics prepared by these two methods has affected the optical transmission rate,and the hot isostatic pressing sintering has high requirements on the equipment.To solve this problem,the phase structure of Tb₂O₃ was stabilized by yttrium oxide,and terbium-based magneto-optic transparent ceramics were prepared by sintering with unpressurized hydrogen.It mainly includes the following steps: synthesis of nanocrystalline powder with high sintering activity by wet chemical co-precipitation technology;preparation of yttrium stabilized terbium oxide??Tbx Y1-x?2O3,YST?magneto-optical ceramics by reducing hydrogen atmosphere sintering.The specific work content is as follows:?1?Tb₂O₃ nanocrystalline powders with good dispersivity,uniform particle size and high sintering activity were prepared by wet chemical coprecipitation with terbium nitrate as parent solution and ammonium bicarbonate and ammonia as composite precipitant.It was found that the precursor powder prepared by wet chemical co-precipitation positive drop method could not be completely decomposed by heat until the calcination temperature reached 950?.Otherwise,the ceramic powder would not be decomposed and contain the precursor that was not crystallized,which would affect the sintering process.The Tb₂O₃ ceramics were sintered in a reduced hydrogen atmosphere,and the sintering temperature reached more than 1600 oC,the ceramic blank would crack or directly pulverized due to phase transition.?2?Yttrium stabilized terbium oxide powder with high dispersion and uniform particle size was prepared by wet chemical coprecipitation with the mixed solution of terbium nitrate and yttrium nitrate as mother solution and ammonium bicarbonate and ammonia as the composite precipitant.Among them,the ceramic light transmittance of?Tb0.5Y0.5?2O3 ceramic element blank obtained by sintering at 1850 oC for 6 hours can reach up to 72.41%,the field constant measured at the wavelength of 632.8nm was 220.19rad/T·m,which was 1.64 times higher than the commercial TGG single crystal.?3?Lutetium stabilized terbium oxide?LST?try to use an oxide?Lu2O3?as a doping aid,which is closer to the mass of Tb atoms.The lutetium stabilized terbium oxide ceramics were prepared by wet chemical coprecipitates?Tb0.5Lu0.5?2O3 powder and sintered at 1850? for 6h without cracking.Furthermore,compared with yttrium oxide,lutetium oxide doped terbium oxide?LST?has better phase structure stability,but the quality of LST magneto optical ceramic optical remains to be strengthened.The sintering process of LST transparent ceramics will be helpful for the preparation of magneto-optical materials with higher Verdet constants.