Role of substrate vicinity on structural evolution and functional properties of lightly doped La_1-xSr_xMnO₃thin films

Epitaxial engineering has been considered an important approach to tune functional properties of oxide thin films. However, there is always a quest of other approaches that can provide more knobs to tailor and explore wide range of novel functional properties. Film substrate symmetry mismatch, thermal coefficient mismatch, substrate termination, and miscut angle and directions are also important factors to modulate growth, structure and functional properties. Here, we present the study on structural and functional properties of lightly doped La_0.9Sr_0.1MnO₃ (LSMO) films on SrTiO₃ substrates with different miscut angles (0.5°, 2°, 4° and 8°). Coherent growth was observed for films on 0.5° miscut substrate and in-plane periodic twining was observed for films grown on higher miscut angles. The out-of-plane periodic twinning was seen for films on for 0.5° miscut substrate while higher miscut substrates promote tilted domains formation. These structural distortions are attributed to monoclinic or triclinic distortion of orthorhombic LSMO films on cubic STO substrates. Curie temperature systematically reduces while magnetoresistance and temperature coefficient increase due to the reduction of domain variants and increase of out of plane tilt angles with the increase of miscut angles.