Magnetic phase transition in MnFeP0.5As0.4Si 0.1

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Date
2010-05-13
Journal Title
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Publisher
Institute of Physics
Abstract
We have carried out a detailed investigation of the magnetic phase transition in MnFeP0.5As0.4Si0.1. Temperature hysteresis has been observed in the variable temperature magnetization curves (Bappl = 0.01 T) with TC W ~ 302 K on warming and TCC ~ 292 K on cooling. The first order nature of this transition in MnFeP0.5As0.4Si0.1 is confirmed by the negative slope obtained from isotherms of M2 versus B/M around the critical temperature. Linear thermal expansion measurements reveal a large volume change, ΔV/V∼8.7×10-3, at the magnetic phase transition and that this magnetovolume effect is suppressed to ΔV/V ∼ 5.5×10-3 in an applied field of Bappl = 1.0 T. Analyses of 57Fe Mössbauer spectra (4.5 - 300 K) using a random distribution model and taking nearest-neighbour environments into account, indicate that the paramagnetic and ferromagnetic phases coexist over a temperature range of ~ 45 K around the Curie temperature. The Debye temperature for MnFeP0.5As0.4Si0.1 has been evaluated as θD = 350 ± 20 K from the temperature dependence of the average isomer shift. ©2010 IOP Publishing Ltd
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Keywords
Phase transformations, Magnetic materials, Thermal expansion, Debye temperature, Fluorescence, Temperature dependence
Citation
Wang, J. L., Campbell, S. J., Tegus, O., Bruck, E., & Dou, S. X. (2010). Magnetic phase transition in MnFeP0.5As0.4Si 0.1. Paper presented to the International Conference on the Applications of the Mossbauer Effect (ICAME 2009), 19th - 24th July 2009. Vienna University of Technology: Vienna, Austria. In Journal of Physics: Conference Series, 217, 12132. doi:10.1088/1742-6596/217/1/012132