Investigation On The Properties Of Magnetostrictive Material Iron-gallium Based On The First-principles Calculations

The influence of temperature on the elastic and thermodynamic properties of magnetostrictive material Iorn-Gallium was investigated by using the first-principles calculations based on the density functional theory?DFT?.In order to investigate the influence of temperature on elastic proerpties,the quasi-harmonic approximation approach was used in our calculations.The obtained lattice parameters,elastic constant and thermal expansion coefficient are in good accordance with available experimental data.In terms of calculated elastic properties,the adiabatic elastic constants and polycrystalline elastic modulus decrease with the increasing temperature.Our calculations showed that the elastic properties were not sensitive to the pressure.We believed that was because the large Young's modulus of FeGa alloy.In addition,FeGa are mechanically stable at room temperature and maintain ductility nature with increasing temperature.However,it should be noted that the DO₃ type Fe₃Ga is more sensitive to temperature,while the elastic properties of L1₂ and DO₁₉ type Fe₃Ga exhibit a very gentle changing trend with increasing temperature.This indicates that L1₂ and DO₁₉9 type Fe₃Ga can keep their mechanical properties through wide temperature range and have good temperature stability.Our study shows that with the increasing of the Ga content,the absolute value of formation energy of FeGa alloy are decreasing.The calculations of elastic constants found that the value of C₁₁1 decreases with the increasing of Ga contents,which indicates that the stability of Fe-Ga along[001]direction is decreasing with the increasing of Ga contents.The shear moduli decrease with increasing the Ga contents,which indicates that the stability of FeGa is decreasing with the increasing of Ga contents.Tetragonal shear elastic constant almost decreases linearly with increasing the Ga contents.It's worth noting that with the increasing of Ga contents,the pseudo-gap between two major peaks in the minority-spin state became softer.The softness bring the Fermi level into a high state,which lowering the stability of the Fe-Ga alloy.