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arXiv · 1206.2024

Magnetic glass in Shape Memory Alloy : Ni45Co5Mn38Sn12

Archana Lakhani·A. Banerjee·P. Chaddah·X. Chen·R. V. Ramanujan
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Abstract

The first order martensitic transition in the ferromagnetic shape memory alloy Ni45Co5Mn38Sn12 is also a magnetic transition and has a large field induced effect. While cooling in the presence of field this first order magnetic martensite transition is kinetically arrested. Depending on the cooling field, a fraction of the arrested ferromagnetic austenite phase persists down to the lowest temperature as a magnetic glassy state, similar to the one observed in various intermetallic alloys and in half doped manganites. A detailed investigation of this first order ferromagnetic austenite (FM-A) to low magnetization martensite (LM-M) state transition as a function of temperature and field has been carried out by magnetization measurements. Extensive cooling and heating in unequal field (CHUF) measurements and a novel field cooled protocol for isothermal MH measurements (FC-MH) are utilized to investigate the glass like arrested states and show a reverse martensite transition. Finally, we determine a field -temperature (HT) phase diagram of Ni45Co5Mn38Sn12 from various magnetization measurements which brings out the regions where thermodynamic and metastable states co-exist in the HT space clearly depicting this system as a 'Magnetic Glass'.

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Archana Lakhani, A. Banerjee, P. Chaddah, X. Chen, R. V. Ramanujan. 2013-01-21. Magnetic glass in Shape Memory Alloy : Ni45Co5Mn38Sn12. https://doi.org/10.1088/0953-8984%2F24%2F38%2F386004

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