Dorj Odkhuu

Engineering of magnetostriction in Fe3Pt1−xIrx by controlling the Ir concentration

A tremendous change in both the sign and magnitude of magnetostriction (λ001) in Fe3Pt1−xIrx (x=0–1.0) was discovered through a first-principles study using the highly precise full-potential linearized augmented plane wave method. The obtained λ001 values span a wide range from −1050 (x=0) to +2670u2002ppm (x=0.25), a significantly large enhancement over the λ001 values attained for Galfenol, a widely investigated material. Further analysis confirmed that this large effect originates mainly from the nonmagnetic Ir and Pt with induced moments, of which the 5d orbital has larger spin–orbit coupling than the 3d orbital of Fe.

First-principles investigation of huge magnetostriction in cubic L12 Fe3Pt

Using the highly precise full-potential linearized augmented plane-wave method, magnetostriction of ferromagnetic shape memory alloy Fe3Pt in the cubic L12 structure is investigated. Being consistent with experiments, the giant magnetostrictive coefficient (λ001) of −1050 ppm was calculated from strain-induced magnetocrystalline anisotropy energy. Microscopic origin of the giant magnetostriction of Fe3Pt is explained by spin-orbit coupling interactions in terms of single particle energy spectra.

Magnetocrystalline Anisotropy of D0

First-principles calculations on the magnetocrystalline anisotropy (MCA) of Fe3Si have been investigated by means of the all-electron full-potential linearized augmented plane-wave method within general gradient approximation. Calculated MCA constants k1 and k2 are 0.33 and -0.17 μeV/Fe, respectively, in consistency with experiment. Easy magnetization axis along the (100) direction was found in a cubic Fe3Si compared to the (110) and (111) magnetization axes. We investigated the strain-dependent MCA energy under tetragonal distortion to predict magnetic easy axis when Fe3 Si grows on a substrate. The calculated MCA energies explain quite well experimental results on Fe3Si systems on GaAs(001) and MgO(001). Magnetic moments, elastic constants, and magnetostriction were found to be quite consistent with experiments.