Micromagnetic and magnetoresistance studies of ferromagneticLa0.83Sr0.13MnO

Scanning probe microscopy was used to investigate the surface topography and micromagnetic structure of La 0 . 8 3 Sr 0 . 1 3 MnO 2 . 9 8 single crystals. The crystals were grown by fused-salt electrolysis and characterizedby chemical analysis, x-ray-diffraction, magnetic and transport measurements, Surface topography of as-grown crystals exhibits well-developed surface corrugations due to extensive twinning. Magnetic force microscopy (MFM) images show that magnetic-domain boundaries are pinned to the crystallographic twins; a small number of unpinned boundaries are observed, The statistical analysis of domain boundary angle distribution is consistent with cubic magnetocrystalline anisotropy for this material. Unusual magnetization behavior in the vicinity of topological defects on the surface is reported. MFM contrast was found to disappear above the ferromagnetic Curie temperature; formation of magnetic structure comprised of Bloch walls of opposite chiralities was observed after quenching.