GREAT MAGNETIC ENTROPY CHANGE IN La(Fe, M)13 (M=Si, Al) WITH Co DOPING
Hu Feng-xiaa,b, Shen Bao-gena, Sun Ji-ronga, Zhang Xi-xiangc
a State Key Laboratory of Magnetism, Institute of Physics & Center of Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China; b Department of Physics, Capital Normal University, Beijing 100037, China; c Physics Department, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
Abstract Very large magnetic entropy change Δ SM, which originates from a fully reversible second-order transition at Curie temperature TC, has been discovered in compounds La(Fe, Si)13, La(Fe, Al)13 and those with Co doping. The maximum change ΔSM\approx19 J·kg-1·K-1, achieved in LaFe11.4Si1.6 at 209K upon a 5T magnetic field change, exceeds that of Gd by more than a factor of 2. The TC of the Co-doped compounds shifts to higher temperatures. ΔSM still has a considerable large magnitude near room temperature. The phenomena of very large ΔSM, convenience of adjustment of TC, and also thesuperiority of low cost, strongly suggest that the compounds La(Fe, M)13 (M=Si, Al) with Co doping are suitable candidates for magnetic refrigerants at high temperatures.