Effect of strain on the electrical transport and magnetization of the epitaxial Pr0.5Ca0.5MnO3∕La0.5Ca0.5MnO3∕Pr0.5Ca0.5MnO3 trilayer structures

Abstract

Epitaxial trilayer structures consisting of two antifferomagnetic charge/orbital order insulators ${\mathrm{Pr}}_{0.5}{\mathrm{Ca}}_{0.5}\mathrm{Mn}{\mathrm{O}}_3$ (PCMO) and ${\mathrm{La}}_{0.5}{\mathrm{Ca}}_{0.5}\mathrm{Mn}{\mathrm{O}}_3$ (LCMO) are grown on (001)-oriented $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ (STO) and $\mathrm{La}\mathrm{Al}{\mathrm{O}}_3$ (LAO) substrates. In this trilayer series, a thin film of LCMO with various thicknesses is sandwiched between the two fixed thicknesses of PCMO. These samples show a Curie temperature with a hysteretic field-dependent magnetization at $10\mathrm{K}$, although the individual compounds are antiferromagnetic. The zero field electronic transport of all samples on LAO shows thermally activated behavior, while the thermally activated behavior is suppressed and a metal-like transport is appearing for the samples on STO as the LCMO layer thickness increases above $10\text{unit}\text{cell}$. We have discussed these magnetic and transport properties of the trilayer structures on STO and LAO by the interfacial effect due to the stabilized CO state and the vibration mode of Jahn-Teller distortion.