Control of the charge/orbital ordering transition in epitaxial La7/8Sr1/8MnO3 thin films through compressive strain

The effect of compressive strain on charge/orbital ordering (COO) transition in epitaxial La7/8Sr1/8MnO3 (LSMO) thin films was investigated. The compressive strain of LSMO thin films grown on LaAlO3 substrates can be modified by varying the film thickness which was verified by x-ray diffraction and Raman scattering measurements. It was found that both the COO transition and magnetic transition of LSMO thin films could be suppressed by the compressive strain and their transition temperatures could be tuned by strain relaxation. The variation of COO transition with compressive strain can be explained by the strain-dependent lattice deformation by structural phase transition. These results indicate that the lattice degree of freedom plays a crucial role in the stabilization of COO phase in LSMO, and will be beneficial to the understanding of the microscopic origin of the COO phase in lightly doped manganites. (paper)