Tuning magnetic and transport properties through strain engineering in La0.7Sr0.3MnO3/La0.5Sr0.5TiO3 superlattices

Superlattices composed of non-magnetic La0.5Sr0.5TiO3 and ferromagnetic La0.7Sr0.3MnO3 were grown by pulsed laser deposition on various substrates to impose different epitaxial strain states. Well-defined superlattice structures with sharp interfaces were observed using scanning transmission electron microscopy and confirmed by electron energy loss spectroscopy. Defects such as misfit dislocations, partial dislocations, and low-angle grain boundaries were found to partially or fully relax the epitaxial strain while dramatically increasing the magnetic coercive field. Conversely, a large tensile strain was seen to induce a tetragonal distortion in the film lattice and alter the magnetic and magneto-transport properties of the superlattices.