Coupling between lattice distortions and magnetism in La 0.9 Sr 0.1 MnO 3 thin films

X-ray scattering experiments have demonstrated that for thin films (100 Å to 500 Å) of La 0.9 Sr 0.1 MnO 3 epitaxially grown on SrTiO 3 (100) substrates, the accommodation of the lattice mismatch between film and substrate gives rise to a modulated structure. The non-bulk-like structural properties of these thin films are the origin of anomalies in the electronic and magnetic behavior. Studies of the lattice as a function of temperature clearly reveal a magnetostrictive effect close to the Curie temperature. For thicker films the strain relief mechanism is replaced by formation of coherent microtwins and some of the bulk properties are recovered, but some differences are still observed.