Magnetic ordering effects in the Raman spectra of Sn1−xCoxO2

Abstract

The room temperature ferromagnetism is observed in chemically synthesized powderlike samples of Sn1−xCoxO2 compound (x=0.07 and 0.1). The Raman spectra of the Sn1−xCoxO2 films were analyzed in terms of their structural and magnetic properties. In the Raman spectra of the Sn1−xCoxO2 films additional features were revealed which are associated with the excitation of phonon modes in the cobalt-oxide-defect complex. The intensities of the Raman bands showed a strong dependence on the doping concentration and on applied magnetic field. The softening of the ∼630cm−1 symmetric A1g mode and the field dependence of the intensity Raman scattering observed for Co-doped SnO2 films was ascribed to spin-phonon interaction. The absorption spectra show that there are changes of absorption edge toward low energy due to the influence of incorporated Co atoms on the electronic states of SnO2. These results can be described by the bound magnetic polarons theory.