Ferromagnetic properties of Ce7Rh3 and Pr7Rh3 single crystals

Ferromagnetic and electrical properties of Ce7Rh3 and Pr7Rh3 single crystals have been investigated by the measurements of magnetization, magnetic susceptibility, electrical resistivity and thermal expansion. As previously reported, the two compounds are ferromagnetic at low temperature. In the ferromagnetic state, Ce7Rh3 has a uniaxial magnetic anisotropy along the c-axis. On the contrary, Pr7Rh3 shows the relatively large in-plane magnetic anisotropy. Magnetic anisotropy energy estimated from the magnetization curves at 4.2 K is Ku1 = 6.32 × 102 erg/cm3 for Ce7Rh3 and Ku2 = 1.90 × 105 erg/cm3 for Pr7Rh3, respectively. Saturation magnetization at 4.2 K is 0.98 μB/Ce for Ce7Rh3 and 1.38 μB/Pr for Pr7Rh3 which are smaller than the gJ value of Ce3+ and Pr3+ free ions indicating the existence of crystal electric field (CEF) effect. Magnetic anisotropy axis of Ce7Rh3 is different from the prediction by the point charge model. This can be described by the 4f-conduction electron hybridization in the c-plane. Electrical resistivity of Ce7Rh3 indicates the existence of the Kondo scattering.