The Effect of the Geometrical Shape and Size of the Cross Section on the Spin-Polarized Transport and the Giant Magnetoresistance : Finite Element Method Analysis
We analyze the effect of the geometrical shape and size of the cross section on the spin-polarized transport and the giant magnetoresistance (GMR) by a finite element method, and evaluate the stability and the physical properties of nano-scale spin valves. We calculate the transmission coefficients in the ballistic regime by using a transfer-matrix method, and evaluate the GMR of the current perpendicular to the plane (CPP) by using a circuit theory. The conduction-band structure is simplified to the potential step, which is determined by combining the interfacial parameters calculated by first-principles with the free electron model. The geometrical shapes of the cross section are line and square. As a result, the cross sectional shape has a significant effect on the spin-polarized transport and the GMR. The square-shaped cross section has an advantage of the large GMR, which is contrary to the line-shaped cross section. These phenomena result from the difference of the cut-off energies with the transverse modes and, consequently, the different spin-down transmission coefficients.
Byung Tae Ahn, Hyeongtag Jeon, Bo Young Hur, Kibae Kim and Jong Wan Park
E. S. Noh et al., "The Effect of the Geometrical Shape and Size of the Cross Section on the Spin-Polarized Transport and the Giant Magnetoresistance : Finite Element Method Analysis", Solid State Phenomena, Vols. 124-126, pp. 843-846, 2007