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Reversible solid-state hydrogen-pump driven by magnetostructural transformation in the prototype system La(Fe,Si)13Hy

Krautz, Maria and Moore, James D. and Skokov, Konstantin P. and Liu, Jian and Teixeira, Cristiano S. and Schäfer, Rudolf and Schultz, Ludwig and Gutfleisch, Oliver (2012):
Reversible solid-state hydrogen-pump driven by magnetostructural transformation in the prototype system La(Fe,Si)13Hy.
In: Journal of Applied Physics, American Institute of Physics, pp. 083918, 112, (8), ISSN 00218979, [Online-Edition: http://dx.doi.org/10.1063/1.4759438],
[Article]

Abstract

n magnetocaloric La(Fe,Si)13 alloys, it is known that hydrogen addition shifts the magnetic transition temperature TC near room temperature. By partial hydrogen desorption, TC can be adjusted precisely towards the working temperature of a magnetic cooling device. In this work, we studied the stability of partially desorbed LaFe11.6Si1.4Hy and show that the large volume difference of ferro- and para-magnetic phases drives the system from a single phase to a stable two-phase configuration. The hydrogen concentration separates on a macroscopic scale. The phase-coexistence is visualized by Kerr Microscopy. Differential scanning calorimetry measurements show that hydrogen can be reversibly recombined and separated again. We explain the separation by the coexistence of a high-volume ferromagnetic and low-volume paramagnetic phase that can be induced either by temperature or other external stimuli. This phenomenon can be applied to material systems that show a coupling of physical and structural transitions.

Item Type: Article
Erschienen: 2012
Creators: Krautz, Maria and Moore, James D. and Skokov, Konstantin P. and Liu, Jian and Teixeira, Cristiano S. and Schäfer, Rudolf and Schultz, Ludwig and Gutfleisch, Oliver
Title: Reversible solid-state hydrogen-pump driven by magnetostructural transformation in the prototype system La(Fe,Si)13Hy
Language: English
Abstract:

n magnetocaloric La(Fe,Si)13 alloys, it is known that hydrogen addition shifts the magnetic transition temperature TC near room temperature. By partial hydrogen desorption, TC can be adjusted precisely towards the working temperature of a magnetic cooling device. In this work, we studied the stability of partially desorbed LaFe11.6Si1.4Hy and show that the large volume difference of ferro- and para-magnetic phases drives the system from a single phase to a stable two-phase configuration. The hydrogen concentration separates on a macroscopic scale. The phase-coexistence is visualized by Kerr Microscopy. Differential scanning calorimetry measurements show that hydrogen can be reversibly recombined and separated again. We explain the separation by the coexistence of a high-volume ferromagnetic and low-volume paramagnetic phase that can be induced either by temperature or other external stimuli. This phenomenon can be applied to material systems that show a coupling of physical and structural transitions.

Journal or Publication Title: Journal of Applied Physics
Volume: 112
Number: 8
Publisher: American Institute of Physics
Uncontrolled Keywords: differential scanning calorimetry, ferromagnetic materials, ferromagnetic-paramagnetic transitions, hydrogen, iron alloys, lanthanum alloys, magnetic transition temperature, magnetocaloric effects, paramagnetic materials, silicon alloys, solid-state phase transformations
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 08:55
Official URL: http://dx.doi.org/10.1063/1.4759438
Identification Number: doi:10.1063/1.4759438
Funders: The research leading to these results has received fund- ing from the European Community’s 7th Framework Programme under Grant Agreement No. 214864 (SSEEC).
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