Robust Bain distortion in the premartensite phase of a platinum-substituted Ni2MnGa magnetic shape memory alloy
Abstract
The premartensite phase of shape memory and magnetic shape memory alloys (MSMAs) is believed to be a precursor state of the martensite phase with preserved austenite phase symmetry. The thermodynamic stability of the premartensite phase and its relation to the martensitic phase is still an unresolved issue, even though it is critical to the understanding of the functional properties of MSMAs. We present here unambiguous evidence for macroscopic symmetry breaking leading to robust Bain distortion in the premartensite phase of 10% Pt-substituted Ni2MnGa. We show that the robust Bain-distorted premartensite (T2) phase results from another premartensite (T1) phase with preserved cubic-like symmetry through an isostructural phase transition. The T2 phase finally transforms to the martensite phase with additional Bain distortion on further cooling. Our results demonstrate that the premartensite phase should not be considered as a precursor state with the preserved symmetry of the cubic austenite phase.
Citation
Singh , S , Dutta , B , D'Souza , S W , Zavareh , M G , Devi , P , Gibbs , A S , Hickel , T , Chadov , S , Felser , C & Pandey , D 2017 , ' Robust Bain distortion in the premartensite phase of a platinum-substituted Ni2MnGa magnetic shape memory alloy ' , Nature Communications , vol. 8 , 1006 . https://doi.org/10.1038/s41467-017-00883-z
Publication
Nature Communications
Status
Peer reviewed
ISSN
2041-1723Type
Journal article
Description
The work was financially supported by the ERC AG 291472 ‘IDEA Heusler! and HeuMem project within the European network M-era.net. The support from DST under its India-DESY scheme through Jawaharlal Nehru Centre for Advanced Scientific Research is acknowledged. B.D. and T.H. gratefully acknowledge Deutsche Forschungsgemeinschaft (DFG) for their funding within the priority program SPP1599. S.S. thanks Alexander von Humboldt foundation, Germany. D.P. acknowledges support from Science and Engineering Research Board of India for financial support through the award of J.C. Bose Fellowship.Collections
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