Physical Properties Of GA₂Based Heusler Alloy

In recent years, ferromagnetic shape memory alloys are receiving increasing attention due to the massive variation of associated magnetoresponsive effects, such as magnetic-field-induced strain effect, magnetic-field-induced shape memory effect, magnetoresistance, Hall effect and exchange bias. These excellent effects have many potential technological applications like magnetic actuators, sensors, magnetic refrigeration. Our work mainly includes the following several aspects:(a) Ga2-based Heusler alloys Ga2XY(X or Y=Ni, Co, Fe, Mn, Cr, V) have been studied in theory. Local Density Approximation (LDA) has been adopted in first-principles calculations. The total energy, tetragonal distortion, electronic structure, magnetism and phonon dispersion of Ga2-based Heusler alloys Ga2XY(X or Y=Ni, Co, Fe, Mn, Cr, V) have been studied by first-principles calculations based on the density functional theory.(b) The phase transformation mechanism and origin of Heusler alloys Ga2XY have been investigated by first-principles calculations at density functional level. For the electronic structure of Ga2XY alloys, we have made a deep analysis and discussion on the evolution of DOS and PDOS with tetragonal distortion.(c) The isostructural alloying method is adopted to alloy two isostructures by substituting Co for V or vice verse, we obtain the middle composition of Ga2MnV0.5Co0.5. The crystal structure, tetragonal distortion, electronic structure, magnetism of Ga2MnV0.5Co0.5are performed using the CASTEP codes based on pseudopotential method with a plane-wave basis set as well as the AKAI-CPA-KKR codes based on the coherent potential approximation (CPA). Meanwhile, we have made a qualitative analysis on whether Ga2MnV0.5Co0.5have phase transition and shape memory effect.