Effects of Zn additions to highly magnetoelastic FeGa alloys

Abstract

Fe1−xMx (M = Ga, Ge, Si, Al, Mo and x ∼ 0.18) alloys offer an extraordinary combination ofmagnetoelasticity and mechanical properties. They are rare-earth-free, can be processed using conventional deformation techniques, have high magnetic permeability, low hysteresis, and low magnetic saturation fields, making them attractive for device applications such as actuators and energy harvesters. Starting with Fe-Ga as a reference and using a rigid-band-filling argument, Zhang et al. predicted that lowering the Fermi level by reducing the total number of electrons could enhance magnetoelasticity. To provide a direct experimental validation for Zhang's hypothesis, elemental additions with lower-than-Ga valence are needed. Of the possible candidates, only Be and Zn have sufficient solubility. Single crystals of bcc Fe-Ga-Zn have beengrown with up to 4.6 at. % Zn in a Bridgman furnace under elevated pressure (15 bars) in order to overcome the high vapor pressure of Zn and obtain homogeneous crystals. Single-crystalmeasurements of magnetostriction and elastic constants allow for the direct comparison of themagnetoelastic coupling constants of Fe-Ga-Zn with those of other magnetoelastic alloys in its class. The partial substitution of Ga with Zn yields values for the magnetoelastic coupling factor, −b 1, comparable to those of the binary Fe-Ga alloy. RightsThis item is authored by federal employees as part of their official duties and are therefore non-copyrightable and/or published by the federal government and now in the public domain.

Effect of Dy doping on magnetostrictive and mechanical properties of Fe83Ga17 alloy

“…In order to solve these issues, an effective method of alloying element addition to Fe-Ga alloys has been much studied. On the one hand, much work has been done to improve the magnetostriction by adding main group elements such as Be, B, C, N, Al, Si, Ge, Sn [10,[12][13][14][15][16][17][18] ; 3d and 4d transition elements such as V, Cr, Mn, Co, Ni, Zn, Nb, Mo, Rh [9,11,14,17,[19][20][21] ; and rare earth elements such as Y, La, Ce, Sm, Tb, Dy, Er [22][23][24][25][26][27][28][29][30][31] . Among the above elements, interstitial elements B, C, and N slightly increase the magnetostriction, but trace doping with rare-earth elements can greatly enhance the magnetostriction of Fe-Ga alloys due to the strong localized magnetocrystalline anisotropy.…”

Investigating enhanced mechanical properties in dual-phase Fe-Ga-Tb alloys

“…Expansion of the tetragonal distortion is the major route to improve the magnetostriction of these materials. Great efforts have been made following this idea by adding 3 d and 4 d transition elements such as V, Cr, Mn, Co, Ni, Cu, Zn, Nb, Mo and Rh1213141516; main group elements such as Be, C, B, N, Si, Al, Ge, Sn171819202122; and rare earth elements such as Y, La, Ce, Tb, Dy…1123242526272829. Trace doping with rare earth elements has been confirmed to be the most effective way to influence the induced tetragonality of the matrix and it greatly enhances the magnetostriction of the Fe-Ga alloys11.…”