Effect of Fe substitution on magnetic and magnetocaloric effect in Gd(Co1-xFex)2B2 compounds

Polycrystalline samples of Gd(Co1-xFex)(2)B-2 (x = 0, 0.1, 0.2, and 0.4) compounds have been prepared and their magnetic properties and magnetocaloric effect (MCE) have been studied by the magnetization and heat capacity measurements. As the Fe content x increases up to 0.4, the magnetic ordering temperature T-M increases gradually from 19 to 32 K, the maximum values of magnetic entropy change -Delta S-M(max) decreases gradually from 17.1 to 12.1 J/kg K without obvious hysteresis around its own T-M for a field change of 5 T, and the corresponding adiabatic temperature change Delta T-ad(max) also decreases gradually from 15.4 to 8 K. The reduction in the MCE of Gd(Co1-xFex)(2)B-2 system could be explained by the fact that the increase in the Fe content transforms the magnetic transition type from a first order type to a second order type. The values of relative cooling power (RCP) are 462, 434, 499, and 415 J/kg for x 0, 0.1, 0.2, and 0.4 in Gd(Co1-xFex)(2)B-2, respectively. The magnetic transition and Fe substitution effect on MCE as well as its potential application in Gd(Co1-xFex)(2)B-2 system were discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3654013]