ﻻ يوجد ملخص باللغة العربية
In planar nano-magnetic devices magnetization direction is kept close to a given plane by the large easy-plane magnetic anisotropy, for example by the shape anisotropy in a thin film. In this case magnetization shows effectively in-plane dynamics with only one angle required for its description. Moreover, the motion can become overdamped even for small values of Gilbert damping. We derive the equations of effective in-plane dynamics in the presence of spin-transfer torques. The simplifications achieved in the overdamped regime allow to study systems with several dynamic magnetic pieces (``free layers). A transition from a spin-transfer device with a static polarizer to a device with two equivalent magnets is observed. When the size difference between the magnets is less than critical, the device does not exhibit switching, but goes directly into the ``windmill precession state.
Non-planar solar-cell devices have been promoted as a means to enhance current collection in absorber materials with charge-transport limitations. This work presents an analytical framework for assessing the ultimate performance of non-planar solar-c
We describe a film of highly-aligned single-walled carbon nanotubes that acts as an excellent terahertz linear polarizer. There is virtually no attenuation (strong absorption) when the terahertz polarization is perpendicular (parallel) to the nanotub
Modulating the polarization of a beam of quantum particles is a powerful method to tailor the macroscopic properties of the ensuing energy flux as it directly influences the way in which its quantum constituents interact with other particles, waves o
An electrical current can transfer spin angular momentum to a ferromagnet. This novel physical phenomenon, called spin transfer, offers unprecedented spatial and temporal control over the magnetic state of a ferromagnet and has tremendous potential i
The current driven magnetisation dynamics of a helical spin-density wave is investigated. Expressions for calculating the spin-transfer torque of real systems from first principles density functional theory are presented. These expressions are used f