Theoretical Study On The Magnetic Properties Of Ferromagnetic/Non-ferromagnetic Interface

In this thesis,we investigated the electronic and magnetic properties of ultrathin Fe film supported by non-noble metal thin film.In addition,we studied the electronic properties of5d oxide NaOsO₃ under external strain.The main results of our works are listed as follows:1.Engineering Giant Magnetic Anisotropy of ultrathin Fe film supported by non-noble metal thin filmWe used six-layer Pb slab to model the Pb?001?substrate and put one to ten Fe monolayers on Pb?001?substrate stacking in the order of FCC structure,denoted as Fe_n/Pb.Our density functional theory calculations were carried out with the Vienna ab-initio simulation package?VASP?.We found that the MAEs of Fe thin films are not closely dependent on thicknesses.Interestingly,the MAEs of Fe₁/Pb and Fe₂/Pb are significantly enhanced to 2.49me V and 4.07meV,respectively,compared to that of Fe thin films?⁰.8meV/slab?.Analysis of the electronic structures,we found that the induced local spin moments on the Pb layers next to the Fe layers are the essential factor for the significant enhancement of MAE in Fe₁/Pb and Fe₂/Pb.Therefore,large MAE is expected if Pb layers exist on both sides of the Fe layers.We considered a series of slab models with repetitive structure of Pb layer?s?capping on the Fe layer?s?,denoted as?Pb_m/Fe_n?_k/Pb,and found that the MAE can be as large as 13.11meV,which is the largest value reported so far,for the Fe based magnetic ultrathin layers.2.Electronic properties of 5d oxide NaOsO₃ under external strainThe orthorhombic perovskite NaOsO₃ undergoes a continuous metal-insulator transition?MIT?,accompanied by G-type antiferromagnetic order at T_N=410 K.It is the second Slater insulator after Cd₂Os₂O₇ was be found.Through first-principles calculations,we studied the electronic structures properties of NaOsO₃,which are substantially affected by structure distortion,and correlation effects.We investigated the strain on the electronic properties.Interestingly,the band gap shows abnormal response when compressive strain is applied.Analysis of electronic and structures reveal that the Os-5d orbitals play the most important role in this phenomenon.