The magnetic entropy change in the double perovskite La2NiMnO6 with strong spin-phonon coupling

The magnetocaloric effect and the critical behavior of La2NiMnO6 are investigated by measurement of the magnetization around T-C. The magnetic entropy change vertical bar Delta S vertical bar of La2NiMnO6 for a field change of 0-45 kOe near the Curie temperature is about 5% of the theoretical expectation. The critical behavior of the La2NiMnO6 deviates from the mean field theory. These abnormal phenomena are understood in the context of the strong spin-phonon coupling in La2NiMnO6. It is suggested that a method of modulating this coupling would enhance the magnetic entropy change greatly, which makes the La2NiMnO6 a promising candidate for room-temperature magnetic refrigeration. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.