Magnetic Domain Structure of La0.7Sr0.3MnO3 thin-films probed at variable temperature with Scanning Electron Microscopy with Polarization Analysis

摘要

The domain configuration of 50 nm thick La0.7SrMnO3 films has been directlyinvestigated using scanning electron microscopy with polarization analysis(SEMPA), with magnetic contrast obtained without the requirement for priorsurface preparation. The large scale domain structure reflects a primarilyfour-fold anisotropy, with a small uniaxial component, consistent withmagneto-optic Kerr effect measurements. We also determine the domain transitionprofile and find it to be in agreement with previous estimates of the domainwall width in this material. The temperature dependence of the image contrastis investigated and compared to superconducting-quantum interference devicemagnetometry data. A faster decrease in the SEMPA contrast is revealed, whichcan be explained by the technique's extreme surface sensitivity, allowing us toselectively probe the surface spin polarization which due to the doubleexchange mechanism exhibits a distinctly different temperature dependence thanthe bulk magnetization.