Effect of substrate-induced strain on transport and magnetic properties of epitaxial La0.66Sr0.33MnO3 thin films

Electrical transport and magnetic properties of epitaxial 500Å La0.67Sr0.33MnO3 (LSMO) thin films, grown on different substrates having different lattice strains, are found to exhibit strong correlation with Jahn-Teller (JT) strain. The authors’ study reveals that a sufficiently large JT strain gives rise to distinct insulating state in LSMO films even below the respective para-ferromagnetic Curie temperature, which is a contradiction with the established phase diagram of Sr doped manganites. The authors have presented a microscopic model for the analysis of their data instead of the usual expansion around the undistorted state. The model incorporates two relevant eg orbitals and the effect of both JT and bulk strains on the transition temperature via double exchange.