Effect of short-range atomic order on macroscopic magnetic properties of equiatomic FePd alloy

ABSTRACT

X-ray diffraction, magnetic measurements, and Mössbauer spectroscopy were employed to comparatively analyse the relation of the basic characteristics of highly anisotropic materials– coercive force H_c and Curie temperature T_C to the peculiarities of short-range atomic order that forms upon annealing of disordered samples of equaiatomic FePd alloys produced by different techniques (casting, melt-spinning, severe deformation). It is shown that for all samples, independently of methods of their preparation, the ordered states with the maximal values of coercivity are inhomogeneous in the composition of short-ordered regions, type of atomic ordering, and degree of tetragonality. The Curie temperature depends on the temperature and duration of annealing for ordering similarly to the conventional course of coercivity, which is peculiar to these alloys. The behaviour of these macroscopic characteristics (H_c and T_C) in the course of annealing is shown to correlate with changes in the local atomic configurations revealed in the Mössbauer spectroscopy experiments.

KEYWORDS:

• Fe-Pd
• FCC – L1₀ phase transformation
• coercivity
• Curie temperature
• Mössbauer spectroscopy

Acknowledgements

The research was carried out within the state assignment of Russia (theme ‘Magnet’ No. АААА-А18-118020290129-5) and partially supported by the Russian Foundation for Basic Research (project No. 17-52-45097)

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Russian Foundation for Basic Research [grant number 17-52-45097]; State Assignment of Minobrnauki of Russia [theme ‘Magnet’ number A18-118020290129-5].