Structural and electrical properties of La0.5Ca0.5MnO3 films deposited on differently oriented SrTiO3 substrates

La0.5Ca0.5MnO3 (LCMO) films of various thicknesses were epitaxially grown on (1 0 0) and (1 1 1) oriented SrTiO3 (STO) substrates by pulsed laser deposition (PLD) technique. It was observed that LCMO films on (1 0 0) STO behave as an insulator. However, the films on (1 1 1) STO show a metal to insulator transition, when their thicknesses exceed 145 nm. Jahn–Teller strain (ɛJ–T) was seen to decrease with increasing film thickness for the films on (1 1 1) STO while the films on (1 0 0) STO have large compressive ɛJ–T values for all thicknesses. Moreover, rocking curves and asymmetries of the diffraction peaks for the films on (1 1 1) STO substrates may indicate the formation of a mosaic structure, which can act as a relaxation mechanism, with the increasing film thickness. These observations suggest that the electronic properties of the LCMO thin films can be modified by structural changes imposed by the substrate.