Great magnetic entropy change in La(Fe, M)(13) (M = Si, Al) with Co doping

Very large magnetic entropy change Delta S-M, which originates from a fully reversible second-order transition at Curie temperature T-C, has been disc overed in compounds La(Fe, Si)(13), La(Fe, Al)(13) and those with Co doping . The maximum change Delta S-M approximate to 19 J.kg(-1).K-1, achieved in LaFe11.4Si1.6 at 209K upon a 5T magnetic field change, exceeds that of Gd b y more than a factor of 2. The T-C of the Co-doped compounds shifts to high er temperatures. Delta S-M still has a considerable large magnitude near ro om temperature. The phenomena of very large Delta S-M, convenience of adjus tment of T-C, and also the superiority of low cost, strongly suggest that t he compounds La(Fe, M)(13) (M=Si, Al) with Co doping are suitable candidate s for magnetic refrigerants at high temperatures.