Phonon activity upon reducing ARuO3-d (A=Ca, Sr)

F. P. DE LA CRUZ; N. E. MASSA; H. SALVA; V. M. NASSIF; S. L. CUFFINI; R. E. CARBONIO

WILEY-V C H VERLAG GMBH

Año: 2000 vol. 220 p. 603 - 603

p>We present infrared reflectivity and transmission spectra from 30 to 25000 cm-1 on the perovskites CaRuO3-d and SrRuO3-d annealed in argon atmosphere and measured at room temperature and 77 K. The structural and physical consequences upon deoxygenetion of  CaRuO3-d and SrRuO3-d are found in the IR spectra as a decrease of the plasma frequency implying fewer effective carriers and the appearence of phonon bands at 337, 873 and 1436 cm-1. This allows us to infer that deoxygenation mechanism generate metal-insulator transitions and perhaps spin reordering. Comparing with the data of untreated CaRuO3 and SrRuO3 samples, the influence of the lattice on the optical conductivity became evident. Our overall results suggest that a polaronic environment may provide for the lower energy extra anomalies in the electrodynamic quantities as recently established by Ahn et al.