Vibrational and magnetic contributions to the entropy change associated with the martensitic transformation of Ni–Fe–Ga ferromagnetic shape memory alloys
Vibrational and magnetic contributions to the entropy change associated with the martensitic transformation of Ni–Fe–Ga ferromagnetic shape memory alloys
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DOI：
10.1088/0953-8984/22/41/416001
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发表时间：
2010-10
期刊：
影响因子：
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通讯作者：
V. Recarte;J. Pérez-Landazábal;C. Gómez-Polo;V. Sánchez-Alarcos;E. Cesari;J. Pons
中科院分区：
文献类型：
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作者：
V. Recarte;J. Pérez-Landazábal;C. Gómez-Polo;V. Sánchez-Alarcos;E. Cesari;J. Pons
Ferromagnetic shape memory alloys undergo a martensitic transformation accompanied by a change in the magnetic and vibrational properties. However, these property changes are not independent. In this paper, the interplay between magnetic and vibrational properties in the martensitic transformation entropy change has been analyzed for Ni–Fe–Ga ferromagnetic shape memory alloys. The martensitic transformation entropy change has a magnetic and a vibrational contribution, . Using a mean field approximation for the magnetic entropy, the full entropy has been decomposed and the magnetic contribution calculated. Upon removing the magnetic term, the vibrational entropy does not change substantially in the composition range where TM is below TC. This latter contribution to the martensitic transformation entropy change has been analyzed using a Debye distribution for the density of states and a proportion of Einstein modes that account for the anomalous phonon mode of the austenite.
