The effect of the microstructure on the antiferromagnetic to ferromagnetic transition in FeRh alloys

Chirkova A, Bittner F, Nenkov K, Baranov NV, Schultz L, Nielsch K, Woodcock TG (2017)

Publication Type: Journal article

Publication year: 2017

Journal

Acta Materialia Elsevier

Book Volume: 131

Pages Range: 31-38

DOI: 10.1016/j.actamat.2017.04.005

Abstract

A detailed study of Fe48Rh52 samples heat treated at different temperatures (1123 K, 1273 K and 1423 K) has been performed using scanning and transmission electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction and magnetic measurements. The microstructure of all samples consisted of α′ (B2) and γ (A1) phases. Although the chemical composition, chemical ordering and the lattice parameter of the magnetic α′ phase in all three samples did not vary with heat treatment temperature, the temperature of the metamagnetic transition between the antiferromagnetic (AFM) and ferromagnetic (FM) states varied by 50 K. No gradients in chemical composition on a length scale larger than approximately 10 nm exist at the α′/γ phase boundaries. Due to the 1% volume expansion of the α′ phase, which occurs during the AFM-FM transition, stress fields around the α′/γ phase boundaries are expected. The composition, lattice parameter, size, shape and distribution of the γ phase was shown to change with heat treatment temperature. Finite element models indicated that these microstructural parameters influence the magnitude and extent of the stress fields at the phase boundaries. The variation in the transition temperature is therefore ascribed to the differences in the stress fields.

Involved external institutions

Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e.V. (IFW) / Leibniz Institute for Solid State and Materials Research Dresden DE Germany (DE) Ural Federal University B.N. Yeltsin RU Russian Federation (RU)

How to cite

APA:

Chirkova, A., Bittner, F., Nenkov, K., Baranov, N.V., Schultz, L., Nielsch, K., & Woodcock, T.G. (2017). The effect of the microstructure on the antiferromagnetic to ferromagnetic transition in FeRh alloys. Acta Materialia, 131, 31-38. https://doi.org/10.1016/j.actamat.2017.04.005

MLA:

Chirkova, Alisa, et al. "The effect of the microstructure on the antiferromagnetic to ferromagnetic transition in FeRh alloys." Acta Materialia 131 (2017): 31-38.

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