Enhancing the charge ordering temperature in thin films of Pr0.5Ca0.5MnO3 by strain

Abstract

We report the effects of biaxial strain on the charge ordering temperature $T_{\mathrm{co}}$ of the mixed-valent manganite perovskite oxide ${\mathrm{Pr}}_{0.5}{\mathrm{Ca}}_{0.5}\mathrm{Mn}{\mathrm{O}}_3$ . Thin films were grown on $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ , which has a 1.3% larger in-plane lattice parameter. Other substrates were used for comparison. Transport measurements combined with data from electron microscopy show that $T_{\mathrm{co}}$ is considerably enhanced. At thicknesses of the order of $10\mathrm{nm}$ , where the films are fully strained, $T_{\mathrm{co}}$ is above $320\mathrm{K}$ , more than $70\mathrm{K}$ above the bulk value of $250\mathrm{K}$ , while around $50\mathrm{nm}$ , where relaxation has set in, the enhancement is around $40\mathrm{K}$ . The bulk value is only reached at a thickness of about $150\mathrm{nm}$ .