Lattice distortion modified anisotropic magnetoresistance in epitaxial La0.67Sr0.33MnO3 thin films

Effects of lattice distortion on the anisotropic magnetoresistance (AMR) of magnetron sputtered epitaxial La0.67Sr0.33MnO3 (LSMO) thin films grown on (001)-oriented SrTiO3 and MgO substrates were investigated. Lattice mismatch at the film/substrate interface gives rise to weak and strong lattice distortion of the LSMO/SrTiO3 and LSMO/MgO films, respectively. The Jahn-Teller electron-phonon coupling in LSMO leads to significant localization of the e(g) electrons, causing smaller magnetization, lower transition temperatures (T-C, T-MI) and larger resistivity. Moreover, AMR of the LSMO films show strong correlations with the substrates. Only two-fold symmetric AMR can be observed in the LSMO/SrTiO3 films. However, the AMR curves of the LSMO/MgO system show clear transitions between two-and four-fold symmetry. This behavior is ascribed to the lattice distortion in the LSMO films which enhances the magnetocrystalline anisotropy. (C) 2017 Elsevier B.V. All rights reserved.