Magnetism, elasticity, and magnetostriction of FeCoGa alloys

Abstract

It is known that the substitution of Co for Fe gives rise to increases in magnetization and Curie temperature, not only in the bcc metals, but also in intermetallic compounds and alloys as well. With the expectation that this is the case in Co-substituted FeGa, we measured magnetization, Curie temperature, magnetostriction and elastic constants of a series of polycrystalline FeCoGa ternary alloys with up to 17% Ga and up to 10% Co. The magnetostriction at saturation for Fe 0.93−x Co .07 Ga x increases to 90 ppm for x=0.17. For larger percentages of Co, the rise in magnetostriction is not as sharp as it is in the 7% case. The shear elastic modulus decreases with Ga, again in keeping with the results for FeGa. The magnetostriction and the elastic constants are sensitive to sample preparation for the high-Ga material. We conclude that the substitution of small (<0.10)percentages of Co for Fe in bcc FeCoGa alloys enhances the magnetic and magnetostrictive properties of the parent FeGa material. It is known that the substitution of Co for Fe gives rise to increases in magnetization and Curie temperature, not only in the bcc metals, but also in intermetallic compounds and alloys as well. With the expectation that this is the case in Co-substituted FeGa, we measured magnetization, Curie temperature, magnetostriction and elastic constants of a series of polycrystalline FeCoGa ternary alloys with up to 17% Ga and up to 10% Co. The magnetostriction at saturation for Fe 0.93Ϫx Co .07 Ga x increases to 90 ppm for xϭ0.17. For larger percentages of Co, the rise in magnetostriction is not as sharp as it is in the 7% case. The shear elastic modulus decreases with Ga, again in keeping with the results for FeGa. The magnetostriction and the elastic constants are sensitive to sample preparation for the high-Ga material. We conclude that the substitution of small (Ͻ0.10) percentages of Co for Fe in bcc FeCoGa alloys enhances the magnetic and magnetostrictive properties of the parent FeGa material.

Electric-field induced strain modulation of magnetization in Fe-Ga/Pb(Mg1/3Nb2/3)-PbTiO3 magnetoelectric heterostructures

“…The in-plane directions exhibited M-H hysteresis behaviors typical of that previously reported for bulk Fe-Ga alloys. [18][19][20][21][22][23] However, the column arrays that stand in the out-of-plane direction resulted in this orientation being magnetically harder. 28 and Fe/BaTiO 3 samples (20%).…”

“…Since the first development by researchers at the magnetic materials group at the Naval Surface Warfare Center (NSWC), Fe-Ga alloys have been a topic of consistent research interests due to a combination of its relatively large magnetostriction, low saturation fields, high mechanical strength, good ductility, and low cost. [18][19][20][21][22][23] In this study, Fe-19%Ga/PMN-30%PT heterostructures were fabricated and their magnetoelectric coupling and the electric field tunability of magnetization via induced strain were investigated. To achieve significant coupling and efficient transfer of strain in these heterostructures, it is essential to choose a ferromagnetic phase with high magnetostriction and a ferroelectric substrate with high piezoelectricity.…”

Magnetostrictive and magnetoelectric behavior of Fe–20at.% Ga∕Pb(Zr,Ti)O3 laminates

“…Recently, a number of investigations have focused on Fe-Ga ͑Galfenol͒ alloys due to the combination of its high mechanical strength, good ductility, relatively large ͑3/2͒ 100 values, low saturation fields, high blocking stress, and low cost. [2][3][4][5][6][7] Galfenol has potential applications in acoustic projectors, acoustic sensors, and actuators. 8,9 Magnetoelectric materials have been very interesting since early Swiss 10 and Russian 11 work, and have recently had a renaissance ͑now commonly called multiferroic͒ in Nature, Science, Phys.…”

Magnetostriction and structural characterization of Fe–Ga–X (X=Co, Ni, Al) mold-cast bulk

“…Polycrystalline Fe-Ga exhibit lower l values than that of single crystals of the same composition, however, still larger than that of pure Fe [2,3]. On the contrary, in polycrystalline alloys small substitutions of Al for Ga and Co for Fe increase l of the Fe-Ga alloys [2,4]. Generally, magnetostriction of polycrystalline materials is very sensitive to the sample preparation, which means to the actual microstructure, but also to the local symmetry, which is changed due to the substitution.…”