Magnetic properties and large inverse magnetocaloric effect in single crystal antiferromagnetic TbNiAl4

The magnetic properties and magnetocaloric effect (MCE) in single crystal antiferromagnetic TbNiAl4 were systematically studied by examining the temperature and field dependence of magnetization and heat capacity. These magnetic properties and the MCE show strong magnetocrystalline anisotropy. A field-induced step-like magnetization transition and large inverse MCE were observed at low temperatures with the magnetic field parallel to the a axis but not for the b or c axes. Such strong anisotropy originates from the crystalline electric field interaction of the Tb3+ ions. The large inverse MCE is related to the field-induced step-like magnetic behaviour which is probably due to a transition from a commensurate antiferromagnetic phase to an incommensurate magnetic phase. The values of maximum magnetic entropy change ( Δ S M max ) reach 5.0 and 7.9 J Kg−1 K−1 for field changes of 2 and 6 T ( H // a axis), respectively; the corresponding maximum adiabatic temperature changes ( Δ T a d max ) are evaluated to be 1.4 and 3.4 K for single crystal TbNiAl4.