Abstract
The structural and magnetic properties for a series of Fe100-xGax alloys (x = 18 – 30 at.%) are studied in the framework of first-principles calculations and Monte Carlo simulations. The both, general gradient approximation and local density approximation are considered for the exchange-correlation functional. The ground state ab initio calculations are performed for both D03 and L12 crystal structures. It is shown that for general gradient approximation, the optimized lattice parameters and total magnetic moments are found in the better agreement with experimental ones. Using the calculated exchange coupling constants for studied compositions, Curie temperatures are estimated by means of Monte Carlo simulations of Heisenberg Hamiltonian.
Highlights
The Fe-Ga alloys are successful magnetostrictive materials which are very attractive to use in magnetostrictive actuators, sensor and spintronic devices [1,2,3,4,5,6,7,8]
Experimental investigations of Fe100-xGax alloys have shown that the value of tetragonal magnetostriction λ001 has two peaks (395×10-6 and 350×10-6) for composition with 19 and 27 at% Ga concentration at room temperature, respectively [2]
We present results obtained by using generalized gradient approximation in the Perdew-Burke-Ernzerhof (GGA-PBE) and LDA-WVN approximations for the exchangecorrelation functional
Summary
The Fe-Ga alloys are successful magnetostrictive materials which are very attractive to use in magnetostrictive actuators, sensor and spintronic devices [1,2,3,4,5,6,7,8]. Doping Ga up to 30 at% into the bcc Fe enhances greatly both the value of tetragonal magnetostriction λ001 in the [001] direction and ductility [1,2,3]. Experimental investigations of Fe100-xGax alloys have shown that the value of tetragonal magnetostriction λ001 has two peaks (395×10-6 and 350×10-6) for composition with 19 and 27 at% Ga concentration at room temperature, respectively [2]. Fe-Ga alloys became the objects of intensive experimental and theoretical studies. The experimental investigations of magnetic and structural properties by means of X-ray diffraction, mechanical spectroscopy techniques, dynamical mechanical analyzer, neutron diffraction, Mössbauer spectroscopy can be found in Refs. The theoretical studies of Fe-Ga and related alloys using first principles approach are presented in Refs. Khmelevska et al [10] proposed the more complex origin of giant magnetostriction in Fe100xGax (0 < x < 25) due to disorder effects in the framework of coherent potential approximation (CPA)
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