Investigation Of Physical Properties Of Full-Heusler Alloys Based On First Principles

The application of the injection materials with 100% spin polarization can effectively improve the spin injection efficiency.Heusler alloys have become excellent candidate material for spin electronic devices due to their highly ordered crystal structure,100% spin polarization and high Curie transition temperature.So far,researchers have carried out a series of theoretical and experimental research on heusler alloys,and found more than 1000 kinds of half-metallic materials.The research on Sc based compound was not very comprehensive,so we took it as the research object,studied their crystal structure,electronic structure,magnetic properties and other physical properties systematically.The main contents are as follows:Firstly,the atomic sites of 171 Sc₂YZ alloys were studied systematically.According to SPR,Sc based Full-Heusler?FH?alloys should form XA structure,because Sc is a transition metal element with less valence electrons,tends to occupy A?0,0,0?and B?0.25,0.25,0.25?,the calculated results are violation of SPR.Secondly,the XA and L21 structures of Sc based FH alloy Sc₂ VGe were studied,and its XA and L21 structures were compared based on the first principles calculation.According to the calculated band structure,the electronic structure and physical properties of the two structures were studied.The magnetism of XA structure was studied,and the influence of uniform strain and tetragonal lattice distortion on the physical properties of XA Sc₂ VGe was studied.The results show that its half metal property is quite stable.Finally,quaternary equiratio FH alloy Sc Fe Rh P was studied.It should be mentioned that there are relatively few reports on quaternary FH alloy.The crystal structure,band structure,the origination of band gap,state density and magnetism were calculated and analyzed.In addition,the change of the physical properties of the compound under uniform strain was studied.The results show that with the change of lattice constant,it has rich physical property transformation.Figure 24;Table 5;Reference 121...