Study On Spin Transport In Diluted Magnetic Semiconductor Magnetic Tunnel Junction

With the rise of spintronics and the development of semiconductor micro-nano devices,spintronics devices show more and more important applications in terms of low labor consumption and structural miniaturization.Spintronics can simultaneously utilize two intrinsic properties of electrons,namely charge conduction properties and spin properties,so as to realize the storage,transmission and processing of high-density information in electronic devices.Sparse magnetic semiconductor magnetic tunnel junction is through 3d transition metal element doping non-magnetic semiconductor materials constitute dilute magnetic semiconductor heterojunction formed through the interface,the dilute magnetic semiconductor or magnetic tunnel junction with spin filter,spin injection and large magnetoresistance effect,this kind of spintronic devices also has the potential application value.Combined with the outstanding characteristics of dilute magnetic semiconductor in spintronic materials,the main research contents are as follows:First,we selected Fe,Co and Ni in 3d transition metal elements,unified content of 12.5%doping concentration of Zn O Zn bit doping,build Zn O dilute magnetic semiconductor,graphic interface VNL structure design of Zn O base dilute magnetic semiconductor,the calculation results show that 12.5% of Fe,Co and Ni atoms doping can improve 4 μ B,2 μ B,1 μ B and 1 μ B,and the doping system magnetic mainly from the 3d orbit of doping atoms.Second,we constructed three sets of magnetic tunnel junction structures stacked along the Z direction,using the Zn O semiconductor as barrier and incorporating Fe,Co and Ni element Zn O-based semiconductors as electrodes and buffer layers.We also used the C graphite structure(100)surface to construct the C / Zn O-Fe / C,C-C / Zn O-Co / C and C / Zn O-Ni / C magnetic tunnel junction structures along the Z direction,adopt the doping concentration of 12.5% to Zn doping,and calculate the electronic structure information and spin transport properties of magnetic tunnel junctions by using density functional theory combined with the non-equilibrium Green function method.Finally,the calculation results show that the magnetic tunnel junctions of the doping system have extremely high spin polarizability,and the doping system shows more excellent spin filtering effect,mainly because the doped magnetic atoms have a single spin direction unpaired electron,which has both spin and charge conduction properties.As the thickness of the intermediate barrier increases,the conduction and spintronic numbers increase,and the magnetic tunnel junction exhibits a better spin filtering effect.The Zn O-based dilute magnetic semiconductor with doped system has potential applications in spintronic devices.