Spin-Dependent Transport Phenomena in Magnetic Nanostructures

A one-dimensional scattering of the incident unpolarized and spin-polarized waves of half spin particles (electrons and neutrons) is applied to doped semiconductors and heterostructures with a homogeneously magnetized potential barriers of layered systems containing magnetic films, interfaces of nano-thicknesses. The potential profiles of these systems have spin-dependent (local) energy barriers, each of which is characterized by its magnetic vector having a longitudinal (parallel to the interface) or/and a transversal (perpendicular to it) components. The magnetic vectors, in general, are noncollinear (in-plane) and even in some cases can become noncoplanar (out-plane) due to the presence of transverse components and in the case of the polarized incident wave the third noncoplanar direction can be defined by vector polarization. The used transfer-matrix allows exactly calculate the coefficient of the electron transmittance and polarization through the system of a single, two and multi magnetic barriers with noncollinear magnetizations. Consequently, the magnetic resonance systems possessing the two or more noncomplanar directions exploiting the giant magnetoresistance effect and other effects caused by the spin polarization of the scattered waves can be used for design of spin valves, filters, diodes and magneto-electronic spin devices. This circumstance leads to new degrees of freedom which make possible to tune the transmission and reflection coefficients and the polarization of the scattered waves, as well. Besides, the noncomplanarity leads to a number of new effects such as interference of the partial scattered waves; tunability of transmission resonance and, in certain conditions, the non-reciprocity of transmission and reflection. For the electron systems the above-mentioned effects are manifested, in particular, in the conductance, polarization, depolarization and the spin reorientation (repolarization or depolarization) of the system and, consequently, can be used for construction of magnetic nanoelements in spintronics. These effects are clearly observable in electron and neutron scatterings at significantly large region of energy and barrier characteristics.