This article is cited in 6 papers

CONDENSED MATTER

Structural and magnetic features of solid-phase transformations in Mn/Bi and Bi/Mn films

V. G. Myagkov^a, L. E. Bykova^a, V. Yu. Yakovchuk^a, V. S. Zhigalov^ba, M. N. Volochaev^ba, A. A. Matsynin^a, I. A. Tambasov^a, V. A. Seredkin^a, G. S. Patrin^ac, G. N. Bondarenko<sup>d

a</sup> Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russia
^b Siberian State Aerospace University, pr. Gazety Krasnoyarskii Rabochii, Krasnoyarsk, 660014, Russia
^c Institute of Chemistry and Chemical Technology, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, 660036, Russia
^d Siberian Federal University, Svobodnyi pr. 79, Krasnoyarsk, 660041, Russia

Abstract: Solid-phase transformations at different annealing temperatures in Mn/Bi (Mn on Bi) and Bi/Mn (Bi on Mn) films have been studied using X-ray diffraction, electron microscopy, and magnetic measurements. It has been shown that the synthesis of the $\alpha$-MnBi phase in polycrystalline Mn/Bi films begins at a temperature of $\sim$120$^\circ$C and the Mn and Bi layers react completely at 300$^\circ$C. The resulting $\alpha$-MnBi(001) samples have a large perpendicular magnetic anisotropy ($K_u\simeq1.5\times10^7$ erg/cm$^3$) and a coercive force $H>H_C\sim3$ kOe. In contrast to Mn/Bi, the ferromagnetic $\alpha$-MnBi phase in Bi/Mn films is not formed even at annealing processes up to 400$^\circ$C and Mn clusters are formed in a Bi melt. This asymmetry in phase transformations occurs because chemosorbed oxygen existing on the surface of the Mn film in Bi/Mn films suppresses a solid-phase reaction between Mn and Bi. The analysis of the results obtained implies the existence of new low-temperature ($\sim$120$^\circ$C) structural transformation in the Mn-Bi system.

Received: 28.12.2015

DOI: 10.7868/S0370274X16040081

 English version: Journal of Experimental and Theoretical Physics Letters, 2016, 103:4, 254–259

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