Magnetocaloric effects on TbCo3-xAlx compounds

The TbCo3-xAlx compounds with x < I crystallize in a rhombohedral structure having R3m space group. The saturation magnetizations, at 4.2 K, increase as cobalt is replaced by aluminium from 3.8 pB/f.u. (x=0) to 6.14 pB/f.u. (x=1) in agreement with antiparallel ordering of Tb and Co sublattices. The magnetic behaviour of cobalt was analyzed in the spin fluctuation model. The adiabatic magnetic entropy changes, IASI, were determined from magnetization data. The largest magnetic entropy change, IASI., was obtained for the sample with x=0.99 which have the Curie temperature around 300 K.