Misfit strain accommodation in epitaxial ABO3 perovskites: Lattice rotations and lattice modulations

We present a study of the lattice response to the compressive and tensile biaxial stress in La0.67Sr0.33MnO3 (LSMO) and SrRuO3 (SRO) thin films grown on a variety of single-crystal substrates: SrTiO3, DyScO3, NdGaO3, and (La,Sr)(Al,Ta)O-3. The results show that, in thin films under misfit strain, both SRO and LSMO lattices, which in bulk form have orthorhombic (SRO) and rhombohedral (LSMO) structures, assume unit cells that are monoclinic under compressive stress and tetragonal under tensile stress. The applied stress effectively modifies the BO6 octahedra rotations, whose degree and direction can be controlled by the magnitude and sign of the misfit strain. Such lattice distortions change the B-O-B bond angles and therefore are expected to affect magnetic and electronic properties of the ABO(3) perovskites.