Magnetic entropy change above 300 K, which is larger than that of gadolinium (Phys. Rev. B 57
(1998) 3478), has been observed in a Cu-doped manganites of La0.7Sr0.3Mn1-xCu xO3 (x = 0.05,0.1). The
large magnetic entropy change originated from a sharp magnetization jump is associated with a first-order
crystallographic phase transition of the sample near the Curie temperature. These results suggest that the
present Cu-doped manganites are suitable candidate materials for magnetic refrigerants in the room
temperature magnetic-refrigeration technology. ?? 2004 Elsevier B.V. All rights reserved
