Magnetization, specific heat, and thermal conductivity of hexagonal ErMnO${}_3$ single crystals

Abstract

We report a study of magnetism and magnetic transitions of hexagonal ErMnO${}_3$ single crystals by magnetization, specific heat and heat transport measurements. Magnetization data show that the $c$-axis magnetic field induces three magnetic transitions at 0.8, 12 and 28 T. The specific heat shows a peak at 2.2 K, which is due to a magnetic transition of Er${}^{3+}$ moments. For low-$T$ thermal conductivity ($\hat{I}º$), a clear dip-like feature appears in $\hat{I}º(H)$ isotherm at 1--1.25 T for $H\parallel ab$; while in the case of $H\parallel c$, a step-like increase is observed at 0.5--0.8 T. The transition fields in $\hat{I}º(H)$ are in good agreement with those obtained from magnetization, and the anomaly of $\hat{I}º$ can be understood by a spin-phonon scattering scenario. The natures of magnetic structures and corresponding field-induced transitions at low temperatures are discussed.

11 pages, 14 figures, accepted for publication in Phys. Rev. B