Study On Half-metallic And Mechanical Properties Of Ternary Heusler Alloys X₂MnAl?X= Cr,Ti? And Their Quaternary Heusler Alloys

In order to meet the requirements of information technology,researchers come to deepen the study on new functional materials.This leads to the birth of the so-called spintronics,which integrates research of both electronic charge and spin state.As is certified,the key to spintronics devices is to obtain materials with high spin injection efficiency.As for materials of the injection source,high spin polarizability is the key.Therefore,Heusler alloy materials,which just meet the above-mentioned requirements,begin to attract much attention.By means of Cambridge Sequential Total Energy Package?CASTEP?of Materials Studio software,based on the first-principles calculation,the half-metallic and mechanical properties of the ternary alloy X₂MnAl?X=Cr,Ti?and the element-doped quaternary alloys CrFeMnAl and TiNiMnAl are studied comprehensively.The corresponding results are as follows:The ternary Heusler alloy Cr₂MnAl is one of the full-Heusler alloy materials.The equilibrium lattice constant is 5.87?,with a band gap width of 0.36 eV and a total magnetic moments of-2?_B.The magnetic properties are mainly from the energy level splitting of the Cr?A?-3d,the Cr?B?-3d and the Mn-3d electronic states near the Fermi level.Besides,Al atoms have little contributions to the total magnetic moment.Mechanical calculations indicate that the Cr₂MnAl alloy should be brittle alloy.The quaternary alloy CrFeMnAl is thought as a full-Heusler alloy material with an equilibrium lattice constant of 5.86?and a zero total magnetic moments.The analysis reveals that the magnetic properties mainly come from the splitting and hybridization of Fe-3d state with Cr-3d state and Mn-3d state near the Fermi level.The calculation of mechanical properties suggest that CrFeMnAl alloy belong to brittle alloy.The ternary Heusler alloy Ti₂MnAl is also one of the half-Heusler materials.The equilibrium lattice constant is 6.26?,with zero total magnetic moments and the band gap width of 0.56 eV.The magnetism is mainly caused by the hybridization of valence electrons of Ti?A?-3d,Ti?B?-3d and Mn 3d near the Fermi level.The mechanical calculation shows that the Ti₂MnAl alloy should be classified as one brittle alloy.Moreover,the quaternary alloy TiNiMnAl is thought as a common magnetic metal material,with an equilibrium lattice constant of 5.89?.The magnetism is caused by the splitting and hybridization of the electrons of Ti-3d,Ni-3d,Mn-3d near the Fermi level.The mechanical calculation reveals that the TiNiMnAl alloy should be also a brittle alloy material.