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Asymmetric first‐order transition and interlocked particle state in magnetocaloric La(Fe,Si) 13
Author(s) -
Waske Anja,
Giebeler Lars,
Weise Bruno,
Funk Alexander,
Hinterstein Manuel,
Herklotz Markus,
Skokov Konstantin,
Fähler Sebastian,
Gutfleisch Oliver,
Eckert Jürgen
Publication year - 2015
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201409484
Subject(s) - magnetic refrigeration , asymmetry , materials science , particle (ecology) , condensed matter physics , first order , synchrotron , volume (thermodynamics) , phase transition , thermodynamics , optics , magnetization , physics , geology , oceanography , mathematics , quantum mechanics , magnetic field
In‐situ synchrotron XRD measurements of the magnetocaloric material LaFe 11.8 Si 1.2 are used to understand virgin effects and asymmetry of the underlying first order magnetovolume transition. A remarkable change of the transition kinetics occurs after the first cycle, which we attribute to the formation of cracks originating from the volume change. Tomographic imaging revealed that the bulk material disintegrates via an interlocked state where fragments are loosely connected. Though cracks have opened between the fragments, the transition is sharp, which we attribute to magnetostatic interactions. In the cycled sample we find a strong asymmetry between the transition interval upon heating and cooling, which we explain by isostatic pressure acting on parts of the sample during the cooling transition. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)