Magnetic ordering effects in the Raman spectra of La 1 − x Mn 1 − x O 3

GRANADO, E.; GARCÍA, A.; SANJURJO, J. A.; RETTORI, C.; TORRIANI, I.; PRADO, F.; SÁNCHEZ, R. D.; CANEIRO, A.; OSEROFF, S. B.

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

APS

Lugar: NY; Año: 1999 vol. 60 p. 11879 - 11882

0163-1829

Temperature-dependent Raman spectra of polycrystalline La1−xMn1−xO3 samples, referred to as LaMnO3+δ for convenience, were correlated to their structural and magnetic properties for different δ. For δ<~0.05, a softening of the ∼610cm−1 Raman mode is observed below the magnetic ordering temperature. This softening is reduced as δ increases from 0.00 to 0.05. This behavior is not associated with lattice anomalies, and is interpreted in terms of a spin-phonon coupling caused by a phonon modulation of the superexchange integral. A quantitative analysis of this effect is presented.