Anisotropic magnetic property, magnetostriction, and giant magnetocaloric effect with plateau behavior in TbMn2Ge2 single crystal

Abstract

AbstractThe ternary RMn2Ge2 (R = rare earth) intermetallic compounds have attracted great attention due to their interesting magnetic behaviors and magnetotransport responses. Here, we reported our observation of anisotropic magnetic property, magnetostriction, and magnetocaloric effect (MCE) in TbMn2Ge2 single crystal. Below the transition temperature of Tb magnetic sublattices ($$T_{{\text{C}}}^{{{\text{Tb}}}}$$ T C Tb  ~ 95 K), strong Ising-like magnetocrystalline anisotropy is observed with an out-of-plane ferromagnetic moments 5.98 μB/f.u. along the easy c axis, which is two orders of magnitude larger than that of field along a axis. Above $$T_{{\text{C}}}^{{{\text{Tb}}}}$$ T C Tb , a field-induced metamagnetic transition is observed from the spin-flip of Mn sublattices. During this transition, remarkable magnetostriction effect is observed, indicating of strong spin–lattice coupling. The responses of Tb and Mn sublattices to the magnetic field generate a giant magnetic entropy change ($$- \Delta S_{M}$$ - Δ S M ) and large values of relative cooling power (RCP) and temperature-averaged entropy change (TEC). The calculated maximum magnetic entropy change ($$- \Delta S_{M}^{\max }$$ - Δ S M max ), RCP, and TEC(10) with magnetic field change of 7 T along c axis reach 24.02 J kg−1 K−1, 378.4 J kg−1, and 21.39 J kg−1 K−1 near $$T_{{\text{C}}}^{{{\text{Tb}}}}$$ T C Tb , which is the largest among RMn2Ge2 families. More importantly, this giant MCE shows plateau behavior with wide window temperatures from 93 to 108 K, making it be an attractive candidate for magnetic refrigeration applications.