Strain effect caused by substrates on phase separation and transport properties in Pr0.7(Ca0.8Sr0.2)0.3MnO3 thin films

Abstract

Tensile and compressive strains were introduced by epitaxially growing Pr(Ca0.8Sr0.2)0.3MnO3 thin films on different substrates with different lattice constants. The large tensile strain in films on SrTiO3 enhances the stability of the long-range charge-orbital (CO) phase and a 5 T magnetic field cannot melt the CO phase. However, the CO phase in the film on (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) is less robust due to a smaller tensile strain and can be partially melt by a 5T field. On the other hand, compressive strained films on LaAlO3 (LAO) show different behavior. Sharp metal-insulator transition with pronounced hysteresis was observed, indicating that the long-range CO is suppressed, whereas the short-rang ferromagnetic (FM)/CO is favored. Upon magnetic field application, resistance reduces remarkably, whereas the insulator-metal (IM) transition and hysteresis becomes broader and insignificant.