Composition dependence of magnetocaloric effect in Sm1-xSrxMnO3(x=0.3-0.5)

We investigated magnetic and magnetocaloric properties in Sm1-xSrxMnO3(x=0.3-0.5). We report a magnetic field-driven first-order metamagnetic transition in the paramagnetic state in x=0.4 and 0.5 and a second-order transition in x=0.3. The highest magnetic entropy (-Delta S-m=1.41 J/mol K for Delta H=5 T at T=125 K) that occurs in x=0.4 is associated with the metamagnetic transition resulting from the field-induced growth and coalescence of ferromagnetic nanoclusters pre-existing in the paramagnetic state. Our results suggest that manganites with intrinsic nanoscale phase separation can be exploited for magnetic refrigeration.