Metamagnetism-enhanced magnetocaloric effect in the rare earth intermetallic compound Ho5Ge4

Magnetic and magnetocaloric properties of polycrystalline Ho5Ge4 (orthorhombic, Sm5Ge4-type, Space group Pnma, No. 62, oP36) compound have been studied. This compound orders antiferromagnetically at similar to 24 K (T-N). From the magnetization vs field isotherms obtained close to the magnetic transition temperature, magnetocaloric effect (MCE) has been estimated. The isothermal magnetic entropy change (Delta S-M) reaches a maximum value of similar to -27 J/kg-K at similar to 30 K for a field change of 140 kOe. A metamagnetic transition is observed in the field dependent magnetization data at temperatures below 20 K, for critical fields above 20 kOe, giving rise to a ferromagnetic order and hence a large MCE. The magnetic moment value at 2.5 K is similar to 8 mu(B)/Ho3+ in 90 kOe field. (C) 2016 Elsevier B.V. All rights reserved.