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.

Effect of Dy substitution in the giant magnetocaloric properties of HoB2

“…For the materials with transition temperatures around 30 K, even though Ho 0.5 Dy 0.5 B 2 shows similar |Δ S M MAX | to Ho 2 Cu 2 Cd [ 18 ] and ErGa [ 31 ], it has a comparable |Δ T ad MAX | to HoAl 2 [ 32 ] and ErCo 2 [ 33 ]. Similarly, Ho 0.3 Dy 0.7 B 2 has almost the same |Δ S M MAX | as HoNi [ 34 , 35 ], however with a much larger |Δ T ad MAX |. In the case of DyB 2 , even though it shows almost half of |Δ S M | compared to Gd 3 Ru [ 36 ], its |Δ T ad MAX | is higher and comparable to DyAl 2 [ 37 ], although both of them are lower than Er 0.53 Ho 0.47 Co 2 [ 38 , 39 ].…”