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Dynamical Effects of the Martensitic Transition in Magnetocaloric Heusler Alloys from DirectΔTadMeasurements under Different Magnetic-Field-Sweep Rates

Gottschall, T. and Skokov, K. P. and Scheibel, F. and Acet, M. and Zavareh, M. Ghorbani and Skourski, Y. and Wosnitza, J. and Farle, M. and Gutfleisch, O. (2016):
Dynamical Effects of the Martensitic Transition in Magnetocaloric Heusler Alloys from DirectΔTadMeasurements under Different Magnetic-Field-Sweep Rates.
In: Physical Review Applied, AMER PHYSICAL SOC, 5, (2), ISSN 2331-7019,
[Online-Edition: http://dx.doi.org/10.1103/PhysRevApplied.5.024013],
[Article]

Abstract

Large magnetocaloric effects can be obtained in Ni-Mn-based Heusler alloys due to the magnetostructural transition between martensite and austenite. This phase transformation proceeds via nucleation and growth. By direct measurements of the adiabatic temperature change Delta T-ad using different magnetic-field-sweeping rates from 0.01 up to 1500 T s(-1), we study the dynamic behavior of the two Heusler compounds Ni50Mn35In15 and Ni45Mn37In13Co5 transforming near room temperature. From these experiments, we conclude that the nucleation process is rather slow in contrast to the relatively fast movement of the phase boundary between martensite and austenite. This is a limiting factor for cooling concepts operating at frequencies beyond 100 Hz. However, the dynamic effects of the transition are negligible in field rates typically used in magnetic refrigeration. These findings are essential considering the suitability of Heusler compounds for energy-efficient solid-state cooling.

Item Type: Article
Erschienen: 2016
Creators: Gottschall, T. and Skokov, K. P. and Scheibel, F. and Acet, M. and Zavareh, M. Ghorbani and Skourski, Y. and Wosnitza, J. and Farle, M. and Gutfleisch, O.
Title: Dynamical Effects of the Martensitic Transition in Magnetocaloric Heusler Alloys from DirectΔTadMeasurements under Different Magnetic-Field-Sweep Rates
Language: English
Abstract:

Large magnetocaloric effects can be obtained in Ni-Mn-based Heusler alloys due to the magnetostructural transition between martensite and austenite. This phase transformation proceeds via nucleation and growth. By direct measurements of the adiabatic temperature change Delta T-ad using different magnetic-field-sweeping rates from 0.01 up to 1500 T s(-1), we study the dynamic behavior of the two Heusler compounds Ni50Mn35In15 and Ni45Mn37In13Co5 transforming near room temperature. From these experiments, we conclude that the nucleation process is rather slow in contrast to the relatively fast movement of the phase boundary between martensite and austenite. This is a limiting factor for cooling concepts operating at frequencies beyond 100 Hz. However, the dynamic effects of the transition are negligible in field rates typically used in magnetic refrigeration. These findings are essential considering the suitability of Heusler compounds for energy-efficient solid-state cooling.

Journal or Publication Title: Physical Review Applied
Volume: 5
Number: 2
Publisher: AMER PHYSICAL SOC
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: 11 May 2016 12:52
Official URL: http://dx.doi.org/10.1103/PhysRevApplied.5.024013
Identification Number: doi:10.1103/PhysRevApplied.5.024013
Funders: This work was supported by DFG (Grant No. SPP 1599) and by HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL).
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