SPECTROSCOPIC STUDIES OF SRTIO3 USING IMPURITY-ION PROBES

Sharp-line fluorescence and absorption in the region of 7935 were observed in Cr3+-doped and undoped SrTiO3. It is reasonably established that the fluorescence and absorption are due to the E2A24 transition (R line) of the Cr3+ ion. Polarization and absorption measurements indicate that the R-line transition is magnetic dipole. Fluorescence from Mn4+-doped SrTiO3 was seen at about 7230. At low temperatures, a temperature-dependent splitting of the R-line transition of Cr3+ is seen. It is shown that this is due to the lifting of the degeneracy of the E2 state by the temperature-dependent tetragonal field present in SrTiO3 below 1032°K. These results are compared with previous measurements on rare-earth ions in SrTiO3. The possible origin of the tetragonal transition is discussed. © 1969 The American Physical Society.