Magnetic properties and magnetocaloric effect in RFe2Ge2 compounds (R=Gd, Tb)

Abstract

The magnetic properties and magnetocaloric effect(MCE) in the ternary intermetallic compounds RFe2Ge2 (R = Gd, Tb) with the body-centered tetragonal ThCr2Si2-type structure were studied. Using the superconducting quantum interference device magnetometer, magnetic field-dependent and temperature-dependent magnetization were measured in range of field 0 - 5 T and temperature 2 - 300 K. The Néel temperature occurring from antiferromagnetic to paramagnetic state is determined to be 10.8 K and 8.5 K for RFe2Ge2 (R = Gd, Tb) compounds, respectively. The field-induced metamagnetic transition from AFM to ferromagnetic state is observed below the Néel temperature, which is indicative of first-order magnetic phase transition. The maximum value of magnetic entropy change and relative cooling power (RCP) are 10.62 J kg-1 K-1 and 159.3 J kg-1 for GdFe2Ge2 and 8.74 J kg-1 K-1 and 201 J kg-1 for TbFe2Ge2 under the variation of the applied field change ΔH = 5 T without magnetic hysteresis loss around the Néel temperature.