Magnetic and magnetocaloric properties of the intermetallic compound TbNiAl

The magnetic and magnetocaloric properties of TbNiAl are studied by investigating the magnetization (M) and entropy change (ΔS) as a function of temperature (T) and magnetic field (H). From the M-T plots, thermogravimetric irreversibility and a few kinks at temperatures lower than T_C, which may be due to the frustrated moments in the compound, is observed. The magnetic ordering temperature (T_N) is found to be 48 K. A sharp metamagnetic transition with a critical field of ∼52 kOe, saturation magnetization of 8.5 μ_B/f.u. and remanence ratio at 2 K are obtained from the M-H curve. The magnetocaloric effect, in terms of ΔS, is calculated from the magnetization isotherm near T_N. The maximum value of ΔS is found to be 13.8 J Kg_-1K_-1 at 50 kOe, and is observed to decrease to 7.1 J Kg_-1K_-1 at 20 kOe.