Magnetocaloric effect in the vicinity of the magnetic phase transition in NdCo2-xFex compounds

In the present paper, the magnetocaloric effect (MCE) of NdCo2-xFex (x=0, 0.2, 0.4, 0.6) compounds was investigated by magnetization measurements. The temperature-dependent high-resolution synchrotron X-ray diffraction study shows a magnetostructural transition from the paramagnetic cubic phase to the ferromagnetic tetragonal phase below their Curie temperatures. Differential scanning calorimetry analysis shows the absence of thermal hysteresis, indicating the second-order nature of the magnetostructural phase transition in these compounds. The maximum values of magnetic entropy change (ΔSM) and wide operating temperature (OT) are obtained under a field change of 5 T, which are 7.33 Jkg-1K-1, 6.45 Jkg-1K-1, 5.71 Jkg-1K-1, 4.70 Jkg-1K-1 and 78 K, 82 K, 85 K, 92 K for x = 0, 0.2, 0.4, and 0.6, respectively. The corresponding values of relative cooling power (RCP) are 529.96 Jkg-1, 497.25 Jkg-1, 470.55 Jkg-1, and 428.31 Jkg-1. The observed wide OT range and large RCP values are comparable with Gd, Gd5Ge2Si2, and some rare-earth-based giant magnetocaloric materials, making this series of compounds suitable for magnetic refrigeration.