Cr3+在SrTiO3晶体中的晶场能级

由激发光谱及荧光光谱的测量,运用Tanabe-Sugano能量矩阵计算了Cr3+在SrTiO3晶体中的晶场能级.

CRYSTAL-FIELD ENERGY LEVELS OF Cr3+ IN SrTiO3 CRYSTAL

Excitation and fluorescence spectra of SrTiO3:Cr3+ crystal were measured at 63 K and 9 K respectively. The crystal-field energy levels of Cr3+ in SrTiO3 crystal were calculated according to Tanobe-Sugano energy matrices and the experimental results.The sample was grown in reduction atmosphere using melt method, which contains nominally 0.01 Wt.% Cr2O3. A 1-mm-thick, polished sample, which was annealed at 660℃ for one to two minutes in air, was used in the experiment. Annealing the sample in air reduces the oxygen vacancies and increases Cr4+ concentration.The crystal-field strength parameter D9 and Racah parameters B and C obtained were 1626, 471 and 2992cm-1 respectively. The ratio Dq/B=3.46>2.3cm-1 means that SrTiO3 crystal belongs to strong field material. The red shift of R line ralative to other Cr3+-doped crystals is about 100 nm. So large red shift was explained to be due to the strong covalence of the SrTiO3 crystal.