Growth And Properties Of Cerium Containing Aluminate Magneto-optical Crystals

This thesis reports the systemic investigations of materials synthesis,crystal growth,magnetism and magneto-optical properties about CeAlO3 and CaTb1-xCexAlO4 crystals.The CeAlO3 polycrystalline materials were synthesized by the Solid-phase synthesis method.XRD,infrared spectrum and DRS were used to measure CeAlO3 polycrystalline materials.We have mastered controllable synthesis process of CeAlO3 polycrystalline materials,which is high purity crystalline phase and meet the requirements of CeAlO3 crystal growth.The CeAlO3 crystal has been grown by the Czochralski technique.And the growth process of CeAlO3 crystal was optimized by adjusting the rotational speed,pulling speed and annealing time,finally,we obtained the high optical quality crystal.At the same time,combined with the growth habit of CeAlO3 crystal simulated by MS software,XRD and rietveld software were used to prove the tetragonal structure of CeAlO3 crystal.We observe a strong characteristic emission peak at 372nm in the fluorescence spectrum of CeAlO3 crystal,which is related to the 5d1-4f radiative transitons of Ce3+ ions in CeAlO3 crystal.The transmittance of CeAlO3 crystal in visible and near infared region is significantly enhanced after annealing in weakly reducing atomsphere,and transimittance is more than 70%.XPS was used to measure the content of valence of crystal for the influence with the transmittance of CeAlO3 crystal after annealing in weakly reducing atmosphere.The magnetic of susceptibility of CeAlO3 crystal in a,c direction at low temperature was measured and analyzed,The temperature dependence of the magnetic susceptibility in a and c directions were measured in the temperature range of 2-300K,which indicated that the CeAlO3 crystal has magnetic anisotropy.At the same time,we found that there is an existence of antiferromagnetic phase transition at Neel temperature about 2K for CeAlO3 crystal.The Faraday rotation angle of the CeAlO3 crystal and CeF3 crystal in the direction of the c optical axis were measured using laser sources at three wavelengths 532,635 and 1064nm at room temperature.The Verdet constant of CeAlO3 crystal is as range from 2.0 to 2.1 times as the TGG crystal.Finally,we discussed the influence of Ce3+ion in ultraviolet region for magneto-optical properties of CeAlO3 crystal.The CaTbAlO4 and CaCeAlO4 polycrystalline materials were synthesized by Solid-phase synthesis method.CaTb1-xCexAlO4 crystals with high optical quality have been grown by the Czochralski technique.XRD,rietveld software were used to calculate the lattice parameters of CaCeAlO4 and CaTb1-xCexAlO4.The chemical formula of crystals were determined by EDS and ICP-AES.We systemic investigate the magnetic properties of CaTb1-xCexAlO4 crystals at room temperature.The transmission spectrum of CaTb1-XCeXAlO4 crystals from 200 to 1600nm were measured.It shows a high transparency is more than 70%from the absorption edge in the 200 and 1600 nm,and presents a characteristic absorption of Tb3+ caused by the energy level transition 7F6?5D4 at 488 nm.The Faraday rotation angle of the CaTb1-xCexAlO4 crystals in the direction of the c optical axis were measured using laser sources at three wavelengths 532,635 and 1064 nm at room temperature.The Verdet constant of CaTb0.955Ce0.045AlO4 and CaTb0.869Ce0.131AlO4 crystal are as 1.05 times and 1.14 times as CaTbAlO4 crystal.According to the DRS and Magnetic circular dichroism preliminary analysis the mechanism of Ce doping increases the Verdet constant of crystal..CeAlO3 and CaTb1-xCexAlO4 crystals may be an applicable magneto-optical material in the visible and near-infrared areas based on high transparent and high Verdet constant.