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

We have studied the magnetocaloric effect (MCE) of single-crystal HoNi, which shows a ferromagnetic transition at T-c = 35K and a spin-reorientation transition at T-SR = 13 K. Below T-c, 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 parallel to a) and b-axes (B parallel to b). the maximum isothermal magnetic-entropy change vertical bar Delta S(M)max vertical bar reaches 22.8 J K-1 kg(-1) at 35K and 18.8 J K-1 kg(-1) at 13K, respectively, when the magnetic field is increased from 0 to 5T. On the other hand, for B parallel to c, vertical bar Delta S-M(max)vertical bar is approximately three times smaller than those for B parallel to a and B parallel to b. In addition, the sign of vertical bar Delta S-M(max)vertical bar depends on the temperature owing to the antiferromagnetic component along the c-axis and the existence of a metamagnetic transition. (C) 2018 The Japan Society of Applied Physics