Work

Effect of charge ordering on crossplane thermal conductivity in correlated perovskite oxide superlattices

Year: 2018

Type: article

Abstract: Lattice thermal conductivity is a sensitive probe of distortions of the translational invariance of crystalline materials. Crossplane thermal conductivity, $\ensuremath{\kappa}(T)$, was studied by the 3\ensuremath{\omega} technique in superlattices, comprising orthorhombic charge/orbital ordered manganite ${\mathrm{Pr}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ and cubic ${\mathrm{SrTiO}}_{3}$. The manganite/titanite superlattices show a peak in $\ensuremath{\kappa}(T)$ just above the charge order transition temperature ${T}_{\mathrm{CO}}\ensuremath{\sim}240\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ with a pronounced thermal hysteresis. This ordering peak in $\ensuremath{\kappa}(T)$ is successively suppressed with decreasing layer thickness. Our results demonstrate a minor effect of the interface density on $\ensuremath{\kappa}$, primarily visible below ${T}_{\mathrm{CO}}$. In contrast, much higher changes in $\ensuremath{\kappa}(T)$ evolve close to ${T}_{\mathrm{CO}}$, due to interface-induced effects on charge and orbital ordering. Our results suggest that the ordering peak in $\ensuremath{\kappa}(T)$ is a result of lattice softening above the phase transition which is modified by thickness-dependent misfit strain.

Source: Physical review. B./Physical review. B

DOI: 10.1103/physrevb.98.195114