Tetragonal magnetostriction and magnetoelastic coupling in Fe-Al, Fe-Ga, Fe-Ge, Fe-Si, Fe-Ga-Al, and Fe-Ga-Ge alloys

Abstract

This paper presents a comparative study on the tetragonal magnetostriction constant,λ γ,2 , [ = (3/2)λ 100 ] and magnetoelastic coupling, b 1 , of binary Fe 100-xZ x (0 < x < 35, Z = Al, Ga, Ge, and Si) and ternary Fe-Ga-Al and Fe-Ga-Ge alloys. The quantities are corrected for magnetostrains due to sample geometry (the magnetostrictive form effect). Recently published elastic constant data along with magnetization measurements at both room temperature and 77 K make these corrections possible. The form effect correction lowers the magnetostriction by ∼10 ppm for high-modulus alloys and by as much as 30 ppm for low-modulus alloys. The elastic constants are also used to determine the values of the magnetoelastic coupling constant, b 1 . With the new magnetostriction data on the Fe-Al-Ga alloy, it is possible to show how the double peak magnetostriction feature of the binary Fe-Ga alloy flows into the single peak binary Fe-Al alloy. The corrected magnetostriction and magnetoelastic coupling data for the various alloys are also compared using the electron-per-atom ratio, e/a, as the common variable. The Hume-Rothery rules link thee/a ratio to the regions of phase stability, which appear to be intimately related to the magnetostriction versus the solute concentration curve in these alloys. Using e/a as the abscissa tends to align the peaks in the magnetostriction and magnetoelastic coupling for the Fe-Ga, Fe-Ge, Fe-Al, Fe-Ga-Al, and Fe-Ga-Ge alloys, but not for the Fe-Si alloys for which the larger atomic size difference may play a greater role in phase stabilization. Corrections for the form effect are also presented for the rhombohedral magnetostriction,λ ɛ,2 , and the magnetoelastic coupling, b 2 , of Fe 100-x Ga x (0 < x < 35) alloys.Keywords aluminium alloys, elastic constants, elastic moduli, gallium alloys, germanium alloys, iron alloys, magnetisation, magnetoelastic effects, magnetostriction, silicon alloys Disciplines Condensed Matter Physics | Metallurgy CommentsThe following article is from Journal of Applied Physics 111 (2012) This paper presents a comparative study on the tetragonal magnetostriction constant, k c,2 , [ ¼ (3/2) k 100 ] and magnetoelastic coupling, b 1 , of binary Fe 100-x Z x (0 < x < 35, Z ¼ Al, Ga, Ge, and Si) and ternary Fe-Ga-Al and Fe-Ga-Ge alloys. The quantities are corrected for magnetostrains due to sample geometry (the magnetostrictive form effect). Recently published elastic constant data along with magnetization measurements at both room temperature and 77 K make these corrections possible. The form effect correction lowers the magnetostriction by $10 ppm for high-modulus alloys and by as much as 30 ppm for low-modulus alloys. The elastic constants are also used to determine the values of the magnetoelastic coupling constant, b 1 . With the new magnetostriction data on the Fe-Al-Ga alloy, it is possible to show how the double peak magnetostriction feature of the binary Fe-Ga alloy flows into the single peak binary Fe-Al alloy. The corrected magnetostriction and magnetoel...

Local deformations and chemical bonding in Fe-X (X = Si, Al, Ga, Ge) soft magnetic alloys

“…The value of c/a tot is the high est for the Fe-Ga alloy, which demonstrates large magnetostriction. However, this characteristic has the lowest absolute value for the Fe-Ge alloy, while the lowest magnetostriction value is observed in the Fe-Si alloy [5]. Thus, the magnitude of c/a tot cannot serve as a parameter responsible for the magnetostriction value.…”

“…Their soft magnetic properties are substantially improved by heat treatment in a dc mag netic field or by mechanical loading due to induced (by an external action) magnetic anisotropy [1][2][3][4]. The Fe-Ga and Fe-Ge alloys are considered to be promising materials for actuators and sensors because of the great magnetostriction effect [5,6]. The causes of the magnetoelastic behavior of these alloys differ, but, in all cases, the formation of a definite type of short range chemical order (SRO) plays an important role [4,[7][8][9].…”

“…The electronic structure and magnetic characteris tics of Fe-X alloys with a definite type of order of atoms of the alloying element X have been studied in a number of works [3][4][5]11]. However, little is known about local deformations that result from the presence of single impurities or their complexes (only work [3] is devoted to the study of the Fe-Si alloy).…”

Contributions from coherent and incoherent lattice excitations to ultrafast optical control of magnetic anisotropy of metallic films

“…1(a)). The equilibrium values of the saturation magnetization M s =1.59 T, the magnetic anisotropy constants K 1 =30 mT, K u =45 mT, the magneto-elastic coefficients b 1 =-6 T, b 2 =2 T were found using literature data [16][17][18] as well as from the fit of the field dependence of the precession frequency.…”

Effect of magnetism on the solution energy of 3p (Al, Si) and 4p (Ga, Ge) elements in iron

“…Their mag netic properties can be significantly improved by heat treatment in a dc magnetic field or under a mechanical load, which leads to enhanced magnetic anisotropy [1][2][3][4] (induced magnetic anisotropy). At the same time in the Fe-Ga and Fe-Ge alloys, in which alloy ing is accompanied by a significant increase in the magnetostriction [5][6][7], the application of an external load does not exert a significant effect on the magnetic anisotropy.…”