Thermal conductivity of PrRh4.8B2, a layered boride compound

Abstract

Transmission electron microscopy (TEM), specific heat, and thermal conductivity measurements were carried out for PrRh4.8B2 single crystals. PrRh4.8B2 takes an interesting layered crystal structure, where PrRh3B2 blocks are separated by metal Rh honeycomb layers. The existence of the Rh layers enhances the ferrimagnetic transition temperature. From area-selective picosecond thermoreflectance, the cross-plane thermal conductivity of PrRh4.8B2 is estimated to be 1.39 Wm−1 K−1, much lower than other layered borides like AlB2. Judging from the fine crystal structures obtained by TEM, phonon conduction is considered to be depressed due to random dispersion of Rh vacancy sites and two-dimensional nature of PrRh4.8B2.