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Spin Relaxation In A Germanium Nanowire, S. Patibandla, S. Pramanik, S. Bandyopadhyay, G. C. Tepper

Electrical and Computer Engineering Publications

We report experimental study of spin transport in nanowirespin valve structures consisting of three layers—cobalt, germanium, and nickel. The spin diffusion length in the Ge is estimated to be about 400nm at 1.9K and the corresponding spin relaxation time is about 4ns. At 100K, the spin diffusion length drops to 180nm and the relaxation time is about 0.81ns. These short relaxation times, which depend weakly on temperature, are caused by strong surface roughness scattering that causes rapid spin relaxation via the Elliott-Yafet mode [Elliott, Phys. Rev.96, 266 (1954)].

Normal And Inverse Spin-Valve Effect In Organic Semiconductor Nanowires And The Background Monotonic Magnetoresistance, Sandipan Pramanik, Supriyo Bandyopadhyay, Kalyan Garre, Marc Cahay

Electrical and Computer Engineering Publications

We have observed both peaks and troughs in the magnetoresistance of organic nanowires consisting of three layers—cobalt, 8-hydroxy-quinolinolato aluminum (Alq3), and nickel. They always occur between the coercive fields of the ferromagnetic layers, and we attribute them to the normal and inverse spin-valve effect. The latter is caused by resonant tunneling through localized impurity states in the organic material. Peaks are always found to be accompanied by a positive monotonic background magnetoresistance, while troughs are accompanied by a negative monotonic background magnetoresistance. This curious correlation suggests that the background magnetoresistance, whose origin has hitherto remained unexplained, is probably caused by …

Surface Band Bending Of A-Plane Gan Studied By Scanning Kelvin Probe Microscopy, S. A. Chevtchenko, X. Ni, Q. Fan, A. A. Baski, Hadis Morkoç

Electrical and Computer Engineering Publications

We report the value of surface band bending for undoped, a-plane GaN layers grown on r-plane sapphire by metalorganic vapor phase epitaxy. The surface potential was measured directly by ambient scanning Kelvin probe microscopy. The upward surface band bending of GaN films grown in the [112¯0] direction was found to be 1.1±0.1V. Because polarization effects are not present on a-plane GaN, we attribute such band bending to the presence of charged surface states. We have modeled the surface band bending assuming a localized level of surface states in the band gap on the surface. It should be noted that the …

Integrating Schedulability Analysis With Uml-Rt, Qimin Gao, Lyndon Brown, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

The use of object oriented techniques and methodologies for the design of real-time control systems appear to be necessary in order to deal with the increasing complexity of such systems. Recently many object-oriented methods have been used for the modeling and design of real-time control systems. We believe that an approach that integrates the advancements in both object modeling and design methods, and real-time scheduling theory is the key to successful use of object oriented technology for real-time software. However, past approaches to integrate the two either restrict the object models, or do not allow sophisticated schedulability analysis techniques. In …