Phase coexistence in strained La0.67Sr0.33MnO3/SrTiO3 (100) thin films

Phase coexistence is typically not observed in the prototypical ferromagnetic manganite La_0.67Sr_0.33MnO${}_3$ (LSMO). To investigate possible strain-induced phase coexistence in LSMO, we grew atomically smooth LSMO thin films with thicknesses ranging from 6 unit cells to 47 unit cells on (100)SrTiO${}_3$ using pulsed laser deposition. Films with thicknesses between 6 and 7 unit cells exhibited anisotropic resistance, depending on the direction of unit cell steps on the film surface. The films also showed step-induced magnetic anisotropy with an easy axis along the step direction. The change in magnetic coercive field with temperature indicated that domain walls were weakly (strongly) pinned when the field was applied parallel (perpendicular) to the steps. Room-temperature magnetic force microscopy revealed step-induced change in the direction of local magnetization. Our results provide a new method for tuning the magnetic and electronic properties of LSMO.