La(Fe1-xCox)11.44Al1.56:: A composite system for Ericsson-cycle-based magnetic refrigerators

The La(Fe1-xCox)(11.44)Al-1.56 system, with x values of 0, 0.04, 0.08, and 0.12, was investigated for its magnetocaloric potential. For selected values of Co doping, it was possible to cover a wide magnetic ordering temperature range, from 200 up to 370 K, and reduce substantially the metamagnetic critical fields. At applied magnetic fields up to 5 T, the maximum magnetic entropy change approaches a nearly constant value of about 5 J/kg K for Co-doped compounds, with x varying from 0.04 to 0.12. The magnetic entropy change of a prototype composite was calculated in order to obtain a constant value in a wide temperature span. The results indicate that this material can be a good candidate for magnetic refrigeration using the Ericsson cycle. (c) 2006 American Institute of Physics.