Role of Gd spin ordering on magnetocaloric effect and ferromagnetism in Sr substituted Gd2CoMnO6 double perovskite

The phenomenon of magnetocaloric effect occurring around the ordering temperatures for Gd2-xSrxCoMnO6 (x = 0 and 0.5) has been investigated in order to disclose the effects of Sr substitution on the individual collinear Gd spin order. It is shown that 25% Sr substitution of Gd ions significantly suppresses the independent spin order, leading to enhancement of ferromagnetism. As a result, magnetic entropy change (Delta S-M) increases from +0.9 J kg(-1) K-1 to +3.7 J kg(-1) K-1 at Curie temperature for a change in magnetic field (Delta H) = 6.9 T. On the other hand, the -Delta S-M changes sign at Neel temperature due to the effect of Sr substitution. We have also observed noticeably large -Delta S-M (similar to+25.84J kg(-1) K-1) and (similar to+21.01 J kg(-1) K-1) for Delta H = 6.9T at 4f-4f negative coupling temperature (T < 10K) of x = 0 and x = 0.5 samples, respectively. Published by AlP Publishing.