Fab rication o f NanocrystallineLa ۰.۶Ca۰.۴M nO۳mang anitesby sol-gel method and stud y of Magnetocalori c effect from indire ct measu rements

Magnetic refrigeration technology based on the mag netocaloric effect shows advantages over traditional gas compression technol ogyand m ay be considered as a prom ising altern ative[۱].Wh en an extern al magnetic field is ap plied to a material, the magnetic spins in the m aterial attempt to align w ith the magnetic field, thereby redu cing the ma gnetic entro py of the spin system.Ifthis process is performed adiabatically, the reduction in spin entropy is offset by an increase in lattice ent ropy, and the temperature of the specimen will rise[۲]. This temperature variation is kno wn as the m agnetocalor ic effect[۳]. Magneticentropy chan ge is know n to achieve relatively high valuesa t the parato ferromagn etic transitio n. The transition temperature ofma nganites may be varied mainly by a chemical composition.

کلیدواژه ها:

Magnetocaloric ، P erovskite ، Nanocrystalline powder ، Magnetic Entropy