Accession Number : AD0676851

Title :   SPECTROSCOPIC STUDIES OF SrTiO3 USING IMPURITY ION PROBES.

Descriptive Note : Technical rept.,

Corporate Author : STANFORD UNIV CALIF MICROWAVE LAB

Personal Author(s) : Stokowski,S. E.

Report Date : MAY 1968

Pagination or Media Count : 121

Abstract : Studies were made of the properties of SrTiO3 using the impurity ions Cr(3+) and Mn(4+) as probes. Sharp line fluorescence and absorption in the region of 7930A were observed in Cr(3+) doped and undoped SrTiO3. Fluorescence from Mn(4+) doped SrTiO3 was also seen at about 7230A. At low temperatures a temperature dependent splitting of the R-line transition of Cr(3+) is seen. It is shown that this is due to the lifting of the degeneracy of the (2)E state by the temperature dependent tetragonal field present in SrTiO3 below 107K. Very unusual and large shifts of the R-lines of Cr(3+) with temperature and applied electric fields were observed. The shifts were found to be proportional to the reciprocal dielectric constant of SrTiO3. The electric field shift is explained in terms of the ionic polarization induced by the electric field. Calculations were made for MgO and SrTiO3 of the possibility of increasing the Cr(3+) R-line transition probability by means of an applied electric field. The possible effect is too small in MgO to be observed experimentally.

Descriptors :   (*PEROVSKITES, *INFRARED SPECTROSCOPY), (*TITANATES, INFRARED SPECTROSCOPY), CRYSTAL DEFECTS, IMPURITIES, CHROMIUM, MAGNESIUM, IONS, ATOMIC ENERGY LEVELS, FLUORESCENCE, ABSORPTION SPECTRA, ELECTRON TRANSITIONS, STRONTIUM COMPOUNDS, CRYSTAL SUBSTRUCTURE

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE