Magnetic transition and magnetocaloric effect of Gd4Sb3-xRx (R=Si, Ge, Sn, 0 ≤ x ≤ 0.75) compounds

The magnetic properties and magnetocaloric effect (MCE) of Gd4Sb3-xRx (R = Si, Ge, Sn, x = 0, 0.25, 0.5, 0.75) compounds have been studied systematically. The Curie temperature (Tc) of these compounds can be tuned from 270 K to 305 K depending on the substitution amount. All the compounds undergo a second-order magnetic transition from ferromagnetic (FM) state to paramagnetic (PM) state and exhibit considerable reversible MCE near room temperature. The maximum of magnetic entropy change (ΔSMmax) for a magnetic field change of 7 T can reach 4.25 Jkg-1K-1 in Gd4Sb3 phase and independent on Si substitution amount. By Ge and Sn substitution, reduced ΔSMmax of 3.5 and 4.25 Jkg-1K-1 can be obtained in Gd4Sb2.75Ge0.25 and Gd4Sb2.75Sn0.25 alloys respectively. The considerable MCE with no hysteresis and working temperature near room temperature suggests that these materials could be promising candidates as ambient magnetocaloric materials.