The MnBi compound exhibits a first-order magneto-structural phase transition around 630 K. This material could be suitable as a rare-earth-free magnetocaloric material provided that one can shift the transition temperature towards room temperature. In this work the effect of a partial substitution of Mn with Ti is investigated. In particular we study the transformation kinetics of the magneto-structural transition, in samples prepared with different techniques: powder metallurgy and rapid quenching from the melt. The samples show a logarithmic dependence of the transition temperature on the temperature scan rate upon cooling. This suggests that the transition occurs with the help of thermal fluctuations. The linear size of the activation volume v0 of these thermally activated processes is found to pass from 2.5 nm in MnBi to around 1.8 nm in Ti substituted samples.

Ti substitution in MnBi rare-earth free magnetocaloric compound / Curcio, C.; Olivetti, ELENA SONIA; Martino, LUCA UGO; Kuepferling, Michaela; Bartok, A.; Lo Bue, M.; Basso, Vittorio. - (2016), pp. 275-278. ((Intervento presentato al convegno Seventh International Conference on Magnetic Refrigeration at Room Temperature, Thermag VII tenutosi a Turin, Italy nel 11-14 September 2016 [10.18462/iir.thermag.2016.0222].

Ti substitution in MnBi rare-earth free magnetocaloric compound

OLIVETTI, ELENA SONIA;MARTINO, LUCA UGO;KUEPFERLING, MICHAELA;BASSO, VITTORIO
2016

Abstract

The MnBi compound exhibits a first-order magneto-structural phase transition around 630 K. This material could be suitable as a rare-earth-free magnetocaloric material provided that one can shift the transition temperature towards room temperature. In this work the effect of a partial substitution of Mn with Ti is investigated. In particular we study the transformation kinetics of the magneto-structural transition, in samples prepared with different techniques: powder metallurgy and rapid quenching from the melt. The samples show a logarithmic dependence of the transition temperature on the temperature scan rate upon cooling. This suggests that the transition occurs with the help of thermal fluctuations. The linear size of the activation volume v0 of these thermally activated processes is found to pass from 2.5 nm in MnBi to around 1.8 nm in Ti substituted samples.
Seventh International Conference on Magnetic Refrigeration at Room Temperature, Thermag VII
11-14 September 2016
Turin, Italy
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11696/54613
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