Strain-induced structural instability in FeRh

Aschauer, Ulrich Johannes; Braddell, Roisin; Brechbühl, Sonia A.; Derlet, Peter M.; Spaldin, Nicola A. (2016). Strain-induced structural instability in FeRh. Physical review. B - condensed matter and materials physics, 94(1) American Physical Society 10.1103/PhysRevB.94.014109

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We perform density functional calculations to investigate the structure of the intermetallic alloy FeRh under epitaxial strain. Bulk FeRh exhibits a metamagnetic transition from a low-temperature antiferromagnetic (AFM) phase to a ferromagnetic phase at 350 K, and its strain dependence is of interest for tuning the transition temperature to the room-temperature operating conditions of typical memory devices. We find an unusually strong dependence of the structural energetics on the choice of exchange-correlation functional, with the usual local density approximation yielding the wrong ground-state structure, and generalized gradient (GGA) extensions being in better agreement with the bulk experimental structure. Using the GGA we show the existence of a metastable face-centered-cubic-like AFM structure that is reached from the ground-state body-centered-cubic-like AFM structure by following the epitaxial Bain path. We show that the behavior is well described using nonlinear elasticity theory, which captures the softening and eventual sign change of the orthorhombic shear modulus under compressive strain, consistent with this structural instability. Finally, we predict the existence of an additional unit-cell-doubling lattice instability, which should be observable at low temperature.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Aschauer, Ulrich Johannes

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
500 Science > 530 Physics

ISSN:

1098-0121

Publisher:

American Physical Society

Language:

English

Submitter:

Ulrich Johannes Aschauer

Date Deposited:

22 Jul 2016 12:59

Last Modified:

08 Aug 2018 10:57

Publisher DOI:

10.1103/PhysRevB.94.014109

ArXiv ID:

1603.01827

BORIS DOI:

10.7892/boris.84462

URI:

https://boris.unibe.ch/id/eprint/84462

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