The First-principles Investigations On Interfacial Electronic Structure Of Magnetic Multilayers

Recently,the emergence of new materials and structures in spintronics has attracted intensive research attention.The magnetic interfaces can be formed between magnetic and various other materials including metal,oxide,semiconductors and topological materials,which exhibit magnetoresistance,large magnetic anisotropy,and current induced switching effect.Therefore,the magnetic interface are promising candidates for low power consumption,high speed and high stability spintronics device applications.In this thesis,several magnetic multilayers have been investigated by first-principles calculations including:topological materials/ferromagnets,heavy metal/antiferromagnets,transition metal oxide/ferromagnets interfaces etc.The first-principles calculations are used to study the density of states,band structure and magnetocrystalline anisotropy of the magnetic multilayers.The following investigations have been performed:1.The perpendicular magnetic anisotropy of 1T'-MoTe₂/Co have been studied:We have find the easy axis is changed from the[100]to the[010]direction in 1T'-MoTe₂/Co(1ML)interface,while the easy axis is still in the out-of-plane[001]direction in 1T'-MoTe₂/Co(3 MLs)interface.2.We investigate the spin-orbit coupling effect and perpendicular magnetic anisotropy of Bi₂Te₃/CoNi₂ multilayers:The interfacial perpendicular magnetic anisotropy energy of2QL/4QL/6QL-Bi₂Te₃ is calculated to be 5.478 erg/cm²,4.034 erg/cm² and 4.073 erg/cm²,respectively.3.We investigate the voltage controlled magnetic anisotroy in Pt(5 MLs)/Mn Pt:We find the Pt/Mn Pt multilayers have in-plane magnetic anisotropy.The easy axis of Pt(5MLs)/Mn Pt(2 u.c.)can be switched between[100]and[110]when proper electric field is applied.4.The interfacial electronic structures of Cu/WO₃/Ni has also been studied:We find the band gap of Cu/WO₃/Ni is about 0.8 e V.At the center of the Brillouin zone,the in-plane spin components show a complex spin structure.5.Finally,we perform calculations on the interlayer exchange coupling of Fe_0.5Co_0.5/W(1-5 MLs)/Fe_0.5Co_0.5:We find when the thickness of W is less than 0.5 nm,the interlayer exchange coupling favor the antiferromagnetic coupling;and when the thickness of W is larger than 0.5 nm,the interlayer exchange coupling becomes ferromagnetic.