无铅In-BCVIG单晶及其磁光特性

LEAD FREE SINGLE CRYSTALS OF INDIUM SUBSTITUTED BCVIG AND THEIR MAGNETO-OPTICAL PROPERTIES

用无铅助熔剂法生长了掺铟的铋钙钒铁石榴石(Bi_(3-2x)Ca_(2x)Fe_(5-x-y)In_yV_xO_(12)单晶,采用本文所述的助熔剂,均长出了线度在10mm以上的晶粒完整、包容物很少的高质单晶。选用x=0.90,y=0.12的单晶,在0.7—2.2 μm波长范围内测量了法拉第磁光旋转角θ_F和光吸收系数α。我们的结果表明无铅In-BCVIG单晶是磁光优值(M=│θ_F│/α)很高的材料。加之还具有低而可变的饱和磁化强度4πM,较高的居里温度Tc,相当大的磁光旋转和低的材料成本, 这些优点将使无铅In-BCVIG在可见光区和近红外区的磁光器件中获得重要应用。

Lead free single crystals of the ferrimagnetic garnet Bi3-2xCa2xFe3-x-yIn,VxO12 are grown by using the flux method. High quality single crystals having a dimension greater than 10 mm and few inclusions can be obtained for all materials with different In content by the technology described in this paper. Faraday rotation and optical absorption of a single crystal with x≈ 0.90, y ≈ 0.12 were measured for wavelength in the range of 0.70 to 2.2 ≈m. In spite of the remarkable increase of rotation by the bismuth substitution, no appreciable increase of absorption coefficient is observed in this wavelength region. Our results demonstrated lead free single crystals of In-BCVIG synthesized in x≈ 1.0 composition region with small amount of In substitution are a magneto-optical material with hige value of magneto-optical figure of merit. Considering its low and variable magnetization, high Curie temprature and rather large magneto-optical rotation, the above results show that the crystals can be employed in magneto-optical devices.