掺Ce稀土铁石榴石块状单晶生长及磁光性能研究

Crystal Growth and Magneto-Optical Properties of ce^(3+) Doped Rare earth Iron Garnet

掺Ce稀土铁石榴石单晶是目前最具发展前景的新型法拉第旋转材料。与GdBiIG,YIG等材料相比,具有更大法拉第旋转、小的温度系数和低廉成本等特点。本文采用改进的助熔剂法,成功地生长出块状Ce:YIG单晶,分析晶体结构,测试近红外波段磁光性能。Ce3+掺入铁石榴石十二面体位极大地增强了材料的法拉第旋转角,在λ=0.78μm时Y3Fe5O12晶体中每一个Ce3+替代Y3+,其θF的增加量(dθF/dx)达到0.6×104deg/cm,是同量Bi3+替代晶体θF增加量的2倍。另外,在稀土铁石榴石中掺入Yb3+和Eu3+,由于其存在弱的还原性,能抑制ce4+的形成,增加Ce3+离子的掺入量。

This paper is concerned with the preparation of cerium doped yttrium iron garnets which are known to be an oxide with large magneto optical effect compared with GdBiIG and YIG. Using the improved flux method we successfully grew the bulk single crystals of iron garnet doped by Ce 3+ ions with maximum substitutions up to 0 349. The spectra of Faraday rotation and optical absorption were measured in the near infrared region for different Ce 3+ ions doped iron garnets. The Ce substitution prominently enhances the Faraday effect, and the enhanced Faraday rotation is as large as 0 6×10 4 deg/cm per Ce ion at λ=0 78μm,which surpasses by a factor of two but opposite in sign to the well known MO enhancement by Bi 3+ in iron garnets at the same wavelength region. Here we investigated the different composition of solution for maximum Ce substitution, and the Yb and Eu ion substitution for Y in the dodecahedral sites of YIG can increase the concentration of Ce 3+ ions, depress the formation of nonmagnetic Ce 4+ ions by the charge compensation.