Magnetocaloric effect in single-crystal HoNi with a canted magnetic structure

Abstract

We have studied the magnetocaloric effect (MCE) of single-crystal HoNi, which shows a ferromagnetic transition at TC = 35 K and a spin-reorientation transition at TSR = 13 K. Below TC, HoNi has ferromagnetic and antiferromagnetic components along the a- and c-axes, respectively. We find that the MCE in HoNi is highly anisotropic owing to the canted magnetic structure of this material. When a magnetic field is applied along the a- (B ∥ a) and b-axes (B ∥ b), the maximum isothermal magnetic-entropy change reaches 22.8 J K−1 kg−1 at 35 K and 18.8 J K−1 kg−1 at 13 K, respectively, when the magnetic field is increased from 0 to 5 T. On the other hand, for B ∥ c, is approximately three times smaller than those for B ∥ a and B ∥ b. In addition, the sign of depends on the temperature owing to the antiferromagnetic component along the c-axis and the existence of a metamagnetic transition.