Abstract
A magnetic entropy change larger than that of gadolinium has been observed in perovskite manganites La0.67-xGdxCa0.33MnO3 (x = 0, 0.05, 0.1, and 0.15) with fixed carrier concentration. The large magnetic entropy change produced by the abrupt reduction of magnetization is attributed to an anomalous thermal expansion at the Curie temperature. This phenomenon indicates that perovskite manganites have some potential applications for magnetic refrigerants in an extended high-temperature range.