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Giant adiabatic temperature change in FeRh alloys evidenced by direct measurements under cyclic conditions

Chirkova, A. and Skokov, K. P. and Schultz, L. and Baranov, N. V. and Gutfleisch, O. and Woodcock, T. G. (2016):
Giant adiabatic temperature change in FeRh alloys evidenced by direct measurements under cyclic conditions.
In: Acta Materialia, PERGAMON-ELSEVIER SCIENCE LTD, pp. 15-21, 106, ISSN 13596454, [Online-Edition: http://dx.doi.org/10.1016/j.actamat.2015.11.054],
[Article]

Abstract

We report on (1) direct measurements of Delta T-ad for binary Fe49Rh51 during field cycling and (2) maximum possible Delta T-ad measured under discontinuous protocol. Our results show that the Delta T-ad is 9.2 K on the first application of magnetic field of Delta mu H-0 = 1.9 T and it remains as high as 6.2 K during the cycling in alternated field of the same magnitude. In addition, the adiabatic temperature change and magnetic entropy change under the first application of magnetic field and under cyclic conditions were determined indirectly using three different approaches: (1) from magnetic measurements (M(T)(H) dependences, Maxwell relations), (2) from calorimetry (C(T)(p,H), S-T diagram) and (3) from H-T diagram. While the indirectly measured maximum possible Delta T-ad lies in the range of 10.5-12 K, the reduced value of Delta T-ad measured directly under cycling (6.2 K) is still extraordinarily high and is 15% higher than in Gd in similar magnetic field. This demonstrates the potential of materials with a first order metamagnetic transition for magnetocaloric applications despite the presence of hysteresis. (C) 2015 Published by Elsevier Ltd on behalf of Acta Materialia Inc.

Item Type: Article
Erschienen: 2016
Creators: Chirkova, A. and Skokov, K. P. and Schultz, L. and Baranov, N. V. and Gutfleisch, O. and Woodcock, T. G.
Title: Giant adiabatic temperature change in FeRh alloys evidenced by direct measurements under cyclic conditions
Language: English
Abstract:

We report on (1) direct measurements of Delta T-ad for binary Fe49Rh51 during field cycling and (2) maximum possible Delta T-ad measured under discontinuous protocol. Our results show that the Delta T-ad is 9.2 K on the first application of magnetic field of Delta mu H-0 = 1.9 T and it remains as high as 6.2 K during the cycling in alternated field of the same magnitude. In addition, the adiabatic temperature change and magnetic entropy change under the first application of magnetic field and under cyclic conditions were determined indirectly using three different approaches: (1) from magnetic measurements (M(T)(H) dependences, Maxwell relations), (2) from calorimetry (C(T)(p,H), S-T diagram) and (3) from H-T diagram. While the indirectly measured maximum possible Delta T-ad lies in the range of 10.5-12 K, the reduced value of Delta T-ad measured directly under cycling (6.2 K) is still extraordinarily high and is 15% higher than in Gd in similar magnetic field. This demonstrates the potential of materials with a first order metamagnetic transition for magnetocaloric applications despite the presence of hysteresis. (C) 2015 Published by Elsevier Ltd on behalf of Acta Materialia Inc.

Journal or Publication Title: Acta Materialia
Volume: 106
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Uncontrolled Keywords: FeRh, Magnetocaloric effect, First-order transitions, Magnetic refrigeration
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Functional Materials
Date Deposited: 11 May 2016 12:27
Official URL: http://dx.doi.org/10.1016/j.actamat.2015.11.054
Identification Number: doi:10.1016/j.actamat.2015.11.054
Funders: This work was partly supported by the Program of the Ural Branch of RAS (Project No 15-17-2-22)., K.S. gratefully acknowledges the financial support of the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST 'MISiS' (K3-2015-029)., O.G. thanks the DFG (SPP1599).
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