Preparation of La0.7Sr0.3Mn1+xOy (1 ⩽ x ⩽ 4) thin films by chemical solution deposition: Dual epitaxy and possible spinodal growth

La0.7Sr0.3Mn1+xOy (1 ⩽ x ⩽ 4) thin films were prepared by chemical solution deposition on LaAlO3 (0 0 1) single crystal substrates. The derived thin films were composed of La0.7Sr0.3MnO3 and Mn3O4 phases when excess Mn content was used as compared to the stoichiometric La0.7Sr0.3MnO3, which could be attributed to a spinodal-like growth mechanism. Both La0.7Sr0.3MnO3 and Mn3O4 phases were epitaxial growth and full relaxation of stress. With increasing Mn content, Mn3O4 phase was squeezed out from matrix and tented to aggregate onto La0.7Sr0.3MnO3 surface. Two magnetic transitions were observed in composite thin films, showing no magnetic coupling between these two phases. Magnetoresistance was only enhanced slightly with increasing Mn content due to slightly enhanced interface effects. It is suggested that the spinodal-like growth will provide a novel route to construct new microstructures in thin films using chemical solution deposition.

► La0.7Sr0.3MnxOy thin films grow in a spinodal-like growth.
► La0.7Sr0.3MnxOy thin films are composed of La0.7Sr0.3MnO3 and Mn3O4.
► Both La0.7Sr0.3MnO3 and Mn3O4 are epitaxial.