Entropy changes accompanying the magnetic phase transitions in low Si-doped Ce2Fe17−xSix Alloy |
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Authors: | Xuezhi Zhou Wanjun JiangHenry Kunkel Gwyn Williams |
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Institution: | Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3 T 2N2 |
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Abstract: | A summary of the results of ac susceptibility and isothermal magnetization measurements on polycrystalline samples of Ce2Fe17−xSix with nominal composition of x=0.0, 0.1, 0.2 and 1.0 is presented. These data reveal that the substitution of small amounts of Si for Fe produce a significant increase in temperature at which ferromagnetism appears, to the extent that, at x=1, characteristics of the anti ferromagnetic to paramagnetic transition (at temperature TN) have disappeared completely. The nature of the various magnetic phase transitions — identified through the use of Arrott plots — and the accompanying magnetic entropy change, ΔSm, are both affected significantly by small amounts of Si substitution. In particular, while the peak entropy change is modest (occurring at x=0.1), the temperature interval over which a substantial entropy change occures is significant, approaching 150 K, an important criterion for improving the overall effectiveness of such materials for magnetic refrigeration. |
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Keywords: | AC susceptibility Magnetocaloric effect Phase transition Magnetic entropy |
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