Metamagnetic Transition And Extremely Large Low Field Magnetocaloric Effect In La0.7ca0.3mno3 Manganite

Metamagnetic transition was observed in low magnetic field for La0.7Ca0.3MnO3-delta lanthanum manganite prepared by solid-state technology. Magnetization shape causes giant low field magnetocaloric effect at Curie temperature T-C=242 K. Magnetic entropy changes Delta S-m, deduced with isothermal magnetization curves, are equal to 7.0 and 8.0 J/kg K in the field change from 0 to 1.0 and 2.0 T, respectively. The obtained Delta S-m are essentially higher than that reported before for lanthanum manganites with similar T-C. The observation shows the way for the construction the magnetic refrigerants, working in the field of permanent magnets, which is beneficial for household and automotive applications. (C) 2008 American Institute of Physics.