La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ Epitaxial Films on SrTiO$_{3}$(001): Interface Effects \& Magnetic Configuration

Mixed valence manganites, in which a delicate interaction between electronic, orbital, magnetic and structural degrees of freedom produces rich phase diagrams reflecting the competing, nearly-degenerate ground states, have been under intense investigation for decades. We present evidence for an unusual magnetic configuration in La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ (LSMO) epitaxial films grown on SrTiO$_{3}$(001) substrates. At low temperatures, the remanent state of the near-surface region in thick LSMO films is aligned anti-parallel to the the applied magnetic field. This unusual magnetic configuration is also correlated with an in-plane structural fluctuation, as measured by x-ray diffraction. We suggest that the unexpected magnetic ordering in these films may also be associated with an orbital reconstruction of the Mn $e_g$ orbitals.