Magnetic,half-metallic And Mechanical Properties Of Full-heusler V₂yga?y=mn,cr?and Its Quaternary Alloys

Recently,with the rapid development of science and technology,various high-tech industries have put forward great demands on the physical properties of novel materials.So,the research&development of novel functional materials becomes more important.It has been found that the Heusler alloy with unique physical properties has gradually attracted people's attention.As is known,Heusler alloy has a high symmetry structure and exhibit distinguished physical effects,such as ferromagnetism,half-metallic properties,thermoelectric effect,magnetoresistance effect,superconductivity,shape memory effect,etc.Therefore,both condensed matter physics and functional materials pay attention to Heusler alloy,which is to search for unique novel functional materials.Based on the first-principles calculation,the magnetic,half-metallic and mechanical properties of V-based ternary Heusler alloy V₂YGa?Y=Mn,Cr?have been simulated by Castep module using Material studio software.Besides,the corresponding properties of the element-doped Heusler alloys VMnCoGa and VMnRhGa have also been investigated in details.The main results are as follows:1.By structural optimization,the minimum total energies of V₂MnGa and V₂CrGa are determined as-26640.58?5?eV and-33895.48?8?eV,respectively,and the corresponding equilibrium lattice constants,5.94?7??and 6.04?1??,respectively.The calculation of partial density of states and band diagram reveals that V₂MnGa is thought as a half-metallic material,the half-metallic band gap is 0.33ev,and the spin polarization is 100%.The total magnetic moments are determined as 2 B,which just meets the Slater-Pauling rules,namelyM_t?28?Z_t-18,while V₂CrGa is a common ferromagnet.2.By analyzing three different atom occupations in the quaternary Heusler alloys VMnCoGa and VMnRhGa,respectively,we show that the structure is the most stable when both alloys adopt the Type 1 occupation.We also determined the formation energies of the both alloys,which give negative value.This indicates that the quaternary Heusler alloys VMnCoGa and VMnRhGa are pratical to be prepared.The results of band structure and density of states represent that the both alloys exhibit magnetic state.Moreover,the magnet moments of both alloys meet the Slater-Pauling rules,i.e.M_t?28?Z_t-24,indicating that the both alloys VMnCoGa and VMnRhGa are nearly half-metals.The mechanical properties show that all V₂YGa?Y=Mn,Cr?and VMnCoGa alloys display good ductility and anisotropic.