Ferromagnetic resonance in thin manganite films: spin-wave excitations, colossal magnetoresistance, and magnetic domains
The Hebrew University of Jerusalem, Israel and Ecole Normale Superieure de Physique and Chimie Industrielle (ESPCI)
Mercredi 12/12/2007, 11:00
SPEC Salle Itzykson, Bât.774, Orme des Merisiers
We study magnetic properties of epitaxial La-Sr-Mn-O films using the ferromagnetic resonance (FMR) technique.
(1) The resonant microwave absorption yields magnetization, anisotropy field and spin-wave stiffness. The latter is compared to the inelastic neutron scattering studies of magnon spectrum in single crystals. (2) The nonresonant microwave absorption in magnetic field is attributed to colossal magnetoresistance (CMR). We develop a model for the CMR in a thin film in oblique magnetic field. Our contactless measurements verify that CMR in LSMO films is nearly isotropic.
(3) The low-field microwave absorption is associated with the ferromagnetic resonance in the multidomain state and yields information on domain size.