Magnetocaloric effect in layered perovskite manganese oxide La1.4Ca1.6Mn2O7

We report the discovery of a large magnetic entropy change in La1.4Ca1.6Mn2O7, a bilayered perovskite manganese oxide that has a Curie temperature (T-C) of about 270 K and which allows magnetic refrigeration at room temperature. The magnetic entropy changes reach values of 11.3 J K-1 kg(-1) and 16.8 J K-1 kg(-1) for field changes of 2 T and 5 T, respectively. The refrigerant capacity of our material is much larger than that of Gd. The large entropy change can be attributed to the fact that the ferromagnetic transition enhances the effect of the applied magnetic field greatly. (C) 2002 American Institute of Physics.