Magnetization, Specific Heat, And Thermal Conductivity Of Hexagonal Ermno3 Single Crystals

We report a study of magnetism and magnetic transitions of hexagonal ErMnO3 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 Er3+ moments. For low-T thermal conductivity (kappa), a clear diplike feature appears in the kappa(H) isotherm at 1-1.25 T for H parallel to ab, while in the case of H parallel to c, a steplike increase is observed at 0.5-0.8 T. The transition fields in kappa(H) are in good agreement with those obtained from magnetization, and the anomaly of kappa can be understood by a spin-phonon scattering scenario. The natures of magnetic structures and corresponding field-induced transitions at low temperatures are discussed.