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Temperature dependent low-field measurements of the magnetocaloric ΔT with sub-mK resolution in small volume and thin film samples

Döntgen, J. and Rudolph, J. and Gottschall, T. and Gutfleisch, O. and Salomon, S. and Ludwig, A. and Hägele, D. (2015):
Temperature dependent low-field measurements of the magnetocaloric ΔT with sub-mK resolution in small volume and thin film samples.
In: Applied Physics Letters, AIP Publishing LLC, pp. 032408, 106, (3), ISSN 0003-6951,
[Online-Edition: http://dx.doi.org/10.1063/1.4906426],
[Article]

Abstract

We present temperature dependent ΔT measurements of the magnetocaloric effect in a thin film sample of Gd, employing magnetomodulation and detection of thermal radiation. A bulk sample of the metamagnetic material LaFe11.05Co0.91Si1.04 shows a strong broadening of the ΔT peak for increasing field amplitudes between 4 and 45 mT. Bulk Gd in comparison shows only a weak broadening. All investigated samples exhibit a clear quadratic dependence of ΔT on the external field H ext at the ΔT peak maximum, contrary to earlier predictions. An analytic expression is derived that interpolates between the H2ext -behavior at low and the well-known H2/3ext -behavior at high fields.

Item Type: Article
Erschienen: 2015
Creators: Döntgen, J. and Rudolph, J. and Gottschall, T. and Gutfleisch, O. and Salomon, S. and Ludwig, A. and Hägele, D.
Title: Temperature dependent low-field measurements of the magnetocaloric ΔT with sub-mK resolution in small volume and thin film samples
Language: English
Abstract:

We present temperature dependent ΔT measurements of the magnetocaloric effect in a thin film sample of Gd, employing magnetomodulation and detection of thermal radiation. A bulk sample of the metamagnetic material LaFe11.05Co0.91Si1.04 shows a strong broadening of the ΔT peak for increasing field amplitudes between 4 and 45 mT. Bulk Gd in comparison shows only a weak broadening. All investigated samples exhibit a clear quadratic dependence of ΔT on the external field H ext at the ΔT peak maximum, contrary to earlier predictions. An analytic expression is derived that interpolates between the H2ext -behavior at low and the well-known H2/3ext -behavior at high fields.

Journal or Publication Title: Applied Physics Letters
Volume: 106
Number: 3
Publisher: AIP Publishing LLC
Uncontrolled Keywords: Temperature measurement, Magnetic films, Magnetic fields, Chemical interdiffusion, Magnetic materials
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: 10 Feb 2015 09:34
Official URL: http://dx.doi.org/10.1063/1.4906426
Identification Number: doi:10.1063/1.4906426
Funders: We gratefully acknowledge financial support by the German Science Foundation (DFG priority program 1599 “Ferroic Cooling”).
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