Analysis of electronic structure and its effect on magnetic properties in (001) and (110) oriented La0.7Sr0.3MnO3 thin films.

Epitaxial thin films of half-metallic oxide La0.7Sr0.3MnO3 (LSMO) have been grown in two crystalline orientations, one with the c-axis out-of-plane, the (001) orientation, and one with the c-axis in-plane, the (110) orientation. For the (110) oriented growth, there is no polar discontinuity at the substrate-film interface and hence no dead layer formation, which improves ferromagnetic interaction in the LSMO, making it highly attractive for spintronic applications. In our experiments, with x-ray diffraction, x-ray photoelectron spectroscopy and magnetic measurements, we have demonstrated that in the (110) oriented LSMO the lattice is more relaxed, leading to less deformation of electronic density around the La atom or in the MnO6 octahedra. This improved crystal and electronic structure improves the ferromagnetic properties of the films, making the Curie temperature higher by almost 15 K, which is of potential interest for spintronics. However, substrate strain induced magnetic anisotropy causes domain formation with out-of-plane components in these films, which poses some concern for practical spintronic devices.