The Study Of Magnetic,Half-metallic And Mechanical Properties Of The Full-heusler Alloys Mn₂MnZ And X₂YAl:Based On The First-principles

Recently,the rapid development of science and technology of the world requires increasing information technology innovation and breakthrough,which makes the big development of information technology products and new functional materials for the industrial product.The traditional microelectronics has reached the upper limit of development,in which the low CPU speed,ill-stability and other factors occur at the current microelectronics.Therefore,a rapid development of new functional materials should be on the agenda.So the spintronics is at present,which balances the charge and spin properties of electrons.The electronic products developed by spintronics will not only greatly improve the processing speed and storage problems,but also greatly improve their stability.Among new functional materials,the Heusler alloys exhibit excellent physical properties,such as extremely high spin polarisation,significant half-metalic property,superconductivity,magnetoresistance effect,thermoelectric effect,shape memory effect,etc.Therefore,the investigation of the Heusler alloys has become one of the important areas in condensed matter physics.In this paper,a first-principles method,based on density functional theory,is applied,using the CASTEP module in the Materials Studio software for simulation modeling,optimization,and calculation.After calculating the magnetic,half-metallic and mechanical properties of full-Heusler alloys Mn₂Mn Z(Z=B,Al,Ga)and X₂Yal(X,Y=Mn,Fe),we obtained the main research results,as follows:1.The equilibrium states corresponding to the lowest energy of Mn₂Mn Z(Z=B,Al,Ga)were detemined by structural optimization.Also,the respective equilibrium lattice constants of 5.46?,5.85?and 5.87?are obtained.The analysis of band structures shows that,Mn₂Mn Al is a ferrimagnetic half-metal material,Mn₂Mn B a ferrimagnetic nearly half-metal material,and Mn₂Mn Ga a ferrimagnetic metallic material.The density of states shows that,the total density of states near the Fermi surface are mainly contributed by the hybridization of the 3d electrons of the Mn₁and Mn₂atoms.The Z-2p state contributes very little to the magnetism.The mechanical calculation shows that,Mn₂Mn Al and Mn₂Mn Ga are anisotropic with good ductibility materials,and Mn₂Mn B is an anisotropic brittle material.2.The lowest energy states of Fe₂FeAl,Mn₂FeAl and Fe₂Mn Al were determined by optimization calculations,and the equilibrium lattice constants of Fe₂FeAl,Mn₂FeAl and Fe₂Mn Al are determined as 5.70?,5.75?and 5.68?,respectively.The energy band structures reveal,Fe₂FeAl is a ferromagnet metallic material,Mn₂FeAl a ferrimagnetic nearly half-metal material,and Fe₂Mn Al is a nearly half-metal magnetic materials.From the density of state analysis,the Al-2p state contributes very little to the magnetism.The total density of state near the Fermi surface is mainly contributed by the state density hybridization of the 3d electrons of the Mn atoms and the Fe atoms The mechanical properties show that Fe₂FeAl,Mn₂FeAl and Fe₂Mn Al are all anisotropic materials with good ductibility.