Using an equation of motion technique, we report on a theoretical analysis of transport characteristics of a spin- valve system formed by a quantum dot coupled to ferromagnetic leads, whose magnetic moments are orient...Using an equation of motion technique, we report on a theoretical analysis of transport characteristics of a spin- valve system formed by a quantum dot coupled to ferromagnetic leads, whose magnetic moments are oriented at an angle θ with respect to each other, and a mesoscopic ring by the Anderson Hamiltonian. We analyse the density of states of this system, and our results reveal that the density of states show some noticeable characteristics depending on the relative angle θ of magnetic moment M, and the spin-polarised strength P in ferromagnetic leads, and also the magnetic flux Φ and the number of lattice sites NR in the mesoscopic ring. These effects might have some potential applications in spintronics.展开更多
In bulk granulated cobaltite La1–xSrxCoO3 with the size of granules of order of 1 micron at strontium hole doping with replacement factor x = 0.35, a transition “metal-nonmetal” in the conductivity was revealed, pr...In bulk granulated cobaltite La1–xSrxCoO3 with the size of granules of order of 1 micron at strontium hole doping with replacement factor x = 0.35, a transition “metal-nonmetal” in the conductivity was revealed, presumably connected with AFM ordering of the moments of granules. The assumption is proved by the agreement between the experiment and results of calculation within the limits of a model offered for electron transport based on the account of in-granule double exchange Zener mechanism and intergranule mechanism of spin-polarized tunneling on the nearest neighbours with AFM exchange interaction. The calculation differs in that conductivities within granules are summarized, while total resistance of the system is represented as a sum of resistances of the granules. In addition, the existence of AFM interaction between granules is supported by the observed insensitivity of conductivity to a low external magnetic field (up to 5 kOe).展开更多
基金supported by the Youth Research Fund of Southwest Petroleum University
文摘Using an equation of motion technique, we report on a theoretical analysis of transport characteristics of a spin- valve system formed by a quantum dot coupled to ferromagnetic leads, whose magnetic moments are oriented at an angle θ with respect to each other, and a mesoscopic ring by the Anderson Hamiltonian. We analyse the density of states of this system, and our results reveal that the density of states show some noticeable characteristics depending on the relative angle θ of magnetic moment M, and the spin-polarised strength P in ferromagnetic leads, and also the magnetic flux Φ and the number of lattice sites NR in the mesoscopic ring. These effects might have some potential applications in spintronics.
文摘In bulk granulated cobaltite La1–xSrxCoO3 with the size of granules of order of 1 micron at strontium hole doping with replacement factor x = 0.35, a transition “metal-nonmetal” in the conductivity was revealed, presumably connected with AFM ordering of the moments of granules. The assumption is proved by the agreement between the experiment and results of calculation within the limits of a model offered for electron transport based on the account of in-granule double exchange Zener mechanism and intergranule mechanism of spin-polarized tunneling on the nearest neighbours with AFM exchange interaction. The calculation differs in that conductivities within granules are summarized, while total resistance of the system is represented as a sum of resistances of the granules. In addition, the existence of AFM interaction between granules is supported by the observed insensitivity of conductivity to a low external magnetic field (up to 5 kOe).
