Magnetic nanowire arrays: A study of magneto-optical properties
Nanocomposite films of highly ordered magnetic nanowires embedded in anodic aluminum oxide templates were fabricated and magneto-optical properties were studied. Following our previous work, studies on Co nanowire arrays were carried out, where the MO properties in relationship with nanowire lengths and diameters were investigated. The results were found to be considerably different from corresponding bulk metal. We demonstrated that the Faraday effect was a convenient and useful probe for the study of the magnetic properties of these semitransparent nanocomposite films. A preliminary study on the photon energy dependence of the magneto-optical properties of Fe nanowire arrays was also conducted in the visible spectrum regime.
We give a simple and complete characterization of the optimum transmitter correlation matrix for multiple-input-multiple-output (MIMO) systems, when antenna subset selection is used. It is assumed that the receiver feeds back to the transmitter only the selected set of antennas without providing any kind of rank ordering of the selected antennas. It turns out that the optimal correlation matrix in this case must be a convex combination of an identity matrix and a matrix whose elements are all ones. This reduces the problem of finding the actual optimum to a one-dimensional search in any given scenario.