The Study Of Magnetic Anisotropy In Two-dimensional Organic Frameworks

With the rapid development of the information society,information technology is important particularly for human beings.The acquisition,transmission and processing of mass information cannot be separated from the storage of information.It can be said that the storage of data is the foundation of information technology.Magnetic storage plays a very important role in information technology in all kinds of storage ways.The enhancement of magnetic recording density has been one of the goals that researchers have spared no effort to overcome.It is also an important research direction in the field of spintronic technology.For magnetic storage materials,the main way to improve the surface density is to reduce the volume of each magnetic recording unit,which requires a larger magnetocrystalline anisotropy energy(MAE)of each magnetic storage unit.Generally,magnetic materials with giant MAE can effectively avoid information loss due to thermal disturbance caused by superparamagnetic effect.Recently,the synthesis and exploration of two-dimensional materials continue to go to a new level.The new two dimensional materials are constantly being synthesized.Because of the outstanding optical,electrical and magnetic properties of two-dimensional materials,it has been applied more and more widely in electronic devices.Especially for two-dimensional transition metal organic compounds,they have wide application prospects in flexible magnetic storage.Based on the first-principle method of density functional theory,the magnetic and MAE of two kinds of two-dimensional organic materials are studied in this paper.(1)The magnetic anisotropy of TM3C12S12 modified by transition metal.Using the first-principle and combined with Torque method,we systematically investigated the magnetic properties of various transition metal elements,including the 3d,4d and 5d metal elements modified TM3C12S12.The study shows that the magnetic properties of the metal elements in the planar quartet field are different,and their magnetic properties are different,especially the 3d transition metal elements,whose planar quartet fields are weak in interaction,and their magnetic moments are changed,while the magnetic moments of the 4d and 5d metal elements are relatively complex.It is proved that the intensity of the plane field interaction can be controlled by the strain field,thus changing the magnetic ordering state.It is interesting that the calculation shows that the magnetocrystalline anisotropy of Re3C12S12 is as high as 13.54 meV,and its MAE can be further improved by applying strain.In particular,when 5%tensile strain is applied,the MAE can reach 20.97meV.Our calculation results indicate that TM3C12S12 has a wide application prospect in magnetic storage.(2)Magnetocrystalline anisotropy of the TM-DCA structure.Based on the first-principles method,we predict the magnetocrystalline anisotropy of a kind of two-dimensional organic TM-DCA material modified by transition metal.The results show that the magnetocrystalline anisotropy of Rh-DCA is as high as 101.90meV.Moreover,because of the strong spin orbit coupling of 4d and 5d elements,the magnetocrystalline anisotropy is relatively large.The behavior of magnetic anisotropy in 5d system is predicted by the rigid band model.The results indicate that TM-DCA is an ideal magnetic storage material.