Effects of Cation Vacancies in the Phonon Raman Spectra of LaMnO3

E. GRANADO; J. SANJURJO; C. RETTORI; F. PRADO; R.D. SANCHEZ; A. CANEIRO; S. OSEROFF

PHYSICA STATUS SOLIDI B-BASIC RESEARCH

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2000 vol. 220 p. 609 - 613

0370-1972

Raman spectra of La1–xMn1–xO3 (x = 0, 0.01, 0.017, 0.022, and 0.035) and La0.91–δMn1–δO3 polycrystalline samples, taken at T = 10 K and room temperature, are presented. AllLa1–xMn1–xO3 samples show at T = 10 K the presence of modes at about 480 and 610cm–1, including the rhombohedral and quasi-cubic orthorhombic samples. However, theRaman spectrum of the rhombohedral La0.91–δMn1–δO3 sample does not show thesemodes at T = 10 K, but presents weak and broad structures at T = 295 K. These resultsare discussed in terms of local structural distortions associated with Mn vacanciesand/or carrier localization in manganese perovskites.