TU Darmstadt / ULB / TUbiblio

Influence of thermal hysteresis and field cycling on the magnetocaloric effect in LaFe11.6Si1.4

Skokov, K. P. and Müller, K.-H. and Moore, J. D. and Liu, J. and Karpenkov, A. Yu. and Krautz, M. and Gutfleisch, O. (2013):
Influence of thermal hysteresis and field cycling on the magnetocaloric effect in LaFe11.6Si1.4.
In: Journal of Alloys and Compounds, Elsevier Science Publishing, pp. 310-317, 552, ISSN 09258388, [Online-Edition: http://dx.doi.org/10.1016/j.jallcom.2012.10.008],
[Article]

Abstract

The adiabatic temperature change ΔTad at a field-induced first-order transition can be different when a magnetic field H is applied the first time compared to measurements under further applications of H. This can lead to overestimation of the magnetocaloric effect (MCE) if only the first field cycle is considered. In polycrystalline LaFe11.6Si1.4, for Δμ0H = 1.93 T, field cycling reduces the achieved value of ΔTad from 7 K to about 5.8 K. A metastable entropy-temperature diagram has been constructed from experimental isofield heat capacity data, which is used to comprehensively analyze results of direct measurements of ΔTad(T)0→H and isothermal magnetization measurements. It is shown that the reduction in ΔTad by field cycling is due to the presence of two-phase states that are stabilized by thermal hysteresis. Relations between optimum operational MCE parameters of a magnetic refrigerant and the maximum available field Havl have been obtained by the approach of an idealized first-order transition.

Item Type: Article
Erschienen: 2013
Creators: Skokov, K. P. and Müller, K.-H. and Moore, J. D. and Liu, J. and Karpenkov, A. Yu. and Krautz, M. and Gutfleisch, O.
Title: Influence of thermal hysteresis and field cycling on the magnetocaloric effect in LaFe11.6Si1.4
Language: English
Abstract:

The adiabatic temperature change ΔTad at a field-induced first-order transition can be different when a magnetic field H is applied the first time compared to measurements under further applications of H. This can lead to overestimation of the magnetocaloric effect (MCE) if only the first field cycle is considered. In polycrystalline LaFe11.6Si1.4, for Δμ0H = 1.93 T, field cycling reduces the achieved value of ΔTad from 7 K to about 5.8 K. A metastable entropy-temperature diagram has been constructed from experimental isofield heat capacity data, which is used to comprehensively analyze results of direct measurements of ΔTad(T)0→H and isothermal magnetization measurements. It is shown that the reduction in ΔTad by field cycling is due to the presence of two-phase states that are stabilized by thermal hysteresis. Relations between optimum operational MCE parameters of a magnetic refrigerant and the maximum available field Havl have been obtained by the approach of an idealized first-order transition.

Journal or Publication Title: Journal of Alloys and Compounds
Volume: 552
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Magnetocaloricl, Phase transitions, Thermal analysis
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Functional Materials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 25 Apr 2013 09:09
Official URL: http://dx.doi.org/10.1016/j.jallcom.2012.10.008
Identification Number: doi:10.1016/j.jallcom.2012.10.008
Funders: The research leading to these results has received funding from the European Community’s 7th Framework Program under grant agreement No. 214864 (SSEEC).
Export:

Optionen (nur für Redakteure)

View Item View Item