Characterization and energy-based model of the magnetomechanical behavior of polycrystalline iron–gallium alloys

Abstract

The actuation and sensing behavior of a typical polycrystalline Fe81.6Ga18.4 alloy sample grown using free stand zone melt (FSZM) manufacturing processes was characterized and its cross-section texture was determined at three transverse stations using electron back-scattering diffraction (EBSD). An attempt was made to model the actuation and sensing behavior of the polycrystalline magnetostrictive sample from its cross-section texture by treating the polycrystal as composed of multiple grains of single crystals, each with a different orientation to the loading axis. The polycrystalline magnetomechanical behavior was modeled as the sum of the volume fraction weighted single-crystal behavior along the [100], [110], [210], [310], [111], [211] and [311] directions, which are modeled using the energy-based approach discussed in Armstrong (1997 J. Appl. Phys. 81 2321) and Atulasimha (2006 PhD Thesis Aerospace Engineering, University of Maryland).

Ultrafast changes of magnetic anisotropy driven by laser-generated coherent and noncoherent phonons in metallic films

“…3 . Note, that the quasi-crystalline structure of our film can decrease the magnetostriction [30], due to decrease of both magnetoelastic and elastic constants, C12 first of all, of such a film [35]. In our case, it leads to insignificant changes of the velocities that do not affect our conclusions.…”

“…In order to get all the anisotropy parameters, we have analyzed the data published for (Fe,Ga) alloys and take the parameters for concentration of Ga atoms equal to 19% as M0=1.59 T, b1= -6 T, b2=2 T [29] and cubic anisotropy K1=30 mT [21,30]. As there is not enough data on the uniaxial anisotropy direction in (311)-FeGa/GaAs films we choose initially in Eq.…”

Tunable fringe magnetic fields induced by converse magnetoelectric coupling in a FeGa/PMN-PT multiferroic heterostructure

“…It should be noted that the addition of pre-stress results in not only an increased magnetostriction but also an increased bias magnetic field needed for reorienting the magnetic moments in the direction of applied magnetic field. 19 Therefore, there is a trade-off between larger tuning of the fringe field, depending on the magnetostriction, and smaller bias magnetic fields. The B-H loop and magnetostriction versus applied magnetic field for FeGa are shown in Figs.…”

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.…”