Cr,Mg:GSGG晶体生长、光谱性能及Cr^(4+)形成机理的研究

Study of growth,spectra properties and Cr^(4+) formation mechanism of Cr,Mg:GSGGcrystal

采用传统提拉法单晶生长技术成功生长出了Cr,Mg:GSGG晶体,并对生长出的晶体样品进行了氧化气氛和还原气氛退火处理.通过对比分析退火处理前后样品吸收光谱的变化,推断出晶体中四面体配位Cr^(4+)离子的形成机理为:晶体生长和高温氧化气氛退火的过程中,四价Cr^(4+)离子首先在八面体格位上形成,然后在热激发作用下与邻近四面体格位上的Ga^(3+)离子发生置换反应,从而形成一定浓度的四面体配位Cr^(4+)离子.实验结果还表明,随着电荷补偿离子Mg^(2+)离子浓度的增大,更有利于提高四面体配位Cr^(4+)离子的浓度.

Cr,Mg：GSGG crystals are successfully grown by the Czochralski method.The influences of reducing- and oxidizing- annealing treatments on the absorption spectra of Cr,Mg：GSGG crystals are investigated.From the changes of their absorption spectra,it can be inferred that the Cr4＋ ions are initially generated at octahedrally coordinated sites,and then exchange positions with tetrahedral Ga3＋ ions in neighboring sites under heat exciting.Differences between absorption spectra also suggest that Mg2＋ ions can improve the concentration of tetrahedral Cr4＋ ions.