Bulk and surface spin excitations in thin films of manganites

✍ Scribed by Aleshkevych, P. ;Baran, M. ;Dyakonov, V. ;Szymczak, R. ;Szymczak, H. ;Baberschke, K. ;Lindner, J. ;Lenz, K.

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 432 KB
• Volume: 203
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200563132

✦ Synopsis

Abstract

A review of experimental studies of magnon excitations in manganites is presented. A microwave resonance technique, in particular a spin‐wave resonance (SWR) technique, is shown to allow the study of not only bulk properties but also surface properties of manganite films. There are two main theoretical approaches used to interpret the SWR spectra: the volume inhomogeneity and the surface inhomogeneity models. The latter, introduced by Puszkarski, allows the interpretation of the observed surface magnon excitations in thin films. It is found that SWR spectra show evidence of manganites, besides bulk spin‐wave modes, and also of surface spin‐waves. This observation is used to determine the surface magnetic anisotropy. The effect of surface anisotropy on the spin‐wave excitation conditions in epitaxial La~0.7~Mn~1.3~O~3–δ~ films is investigated in detail. SWR data give indirect evidence of periodic charge‐ordered stripe forma‐tion. A strong effect of thermal annealing on stripe structure is observed and discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)