Magnetocaloric effect of Gd12Co7

The sample of Gd12Co7 prepared by arc-melting and annealed for 60 days at 873 K was investigated by X-ray diffraction (X-ray), scanning electron microscope (SEM) and energy disperse spectroscopy (EDS). The result shows that the sample of Gd12Co7 in our work is almost single phase with the Ho12Co7-type monoclinic structure. The Magnetocaloric effect of Gd12Co7 was investigated by vibrating-sample magnetometer (VSM) from 100 to 280 K in different applied magnetic fields. The ferromagnetic-paramagnetic transition temperature in a field of 0.1T is about 163 K. The maximum magnetic-entropy change, vertical bar Delta S-M.max vertical bar. of Gd12Co7 is 2.96J kg(-1) K-1 and 4.60J kg(-1) K-1 for a field change of 0-1 T and 0-2 T, respectively. The Arrott plots show that magnetic phase transition of Gd12Co7 is second-order. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.