Magnetocaloric effect in La1-xSrxMnO3 for x=0.13 and 0.16

Magnetization of polycrystalline La1-xSrxMnO3 samples with x=0.13 and x=0.1 6 has been measured as a function of temperature and external magnetic fiel d. Using the gathered data and the thermodynamic Maxwell's relation, change s of the magnetic contribution to entropy under influence of the magnetic f ield, allowing to estimate the value of magnetocaloric effect, have been de termined. The changes reach similar to 7 J/(kg K) in the field of 7 T, whic h makes the studied samples good candidates for application for magnetic re frigeration. Expressions describing entropy and its change under influence of magnetic field have been derived in the molecular field approximation. S atisfactory agreement between the theoretical curves and the experimental d ependencies has been found. (C) 2000 American Institute of Physics. [S0003- 6951(00)00833-0].