Some further remarks on genus field

AbstractGurak's characterization of the relative (narrow) genus field of a normal extension is extended to any finite extension. Using this, a purely algebraic proof for a theorem of the author on the (narrow) genus field is given

Landauer-B\"uttiker approach for hyperfine mediated electronic transport in the integer quantum Hall regime

The interplay of spin-polarized electronic edge states with the dynamics of the host nuclei in quantum Hall systems presents rich and non-trivial transport physics. Here, we develop a Landauer-B\"uttiker approach to understand various experimental features observed in the integer quantum Hall set ups featuring quantum point contacts. The approach developed here entails a phenomenological description of spin resolved inter-edge scattering induced via hyperfine assisted electron-nuclear spin flip-flop processes. A self-consistent simulation framework between the nuclear spin dynamics and edge state electronic transport is presented in order to gain crucial insights into the dynamic nuclear polarization effects on electronic transport and in turn the electron-spin polarization effects on the nuclear spin dynamics. In particular, we show that the hysteresis noted experimentally in the conductance-voltage trace as well as in the resistively detected NMR lineshape results from a lack of quasi-equilibrium between electronic transport and nuclear polarization evolution. In addition, we present circuit models to emulate such hyperfine mediated transport effects to further facilitate a clear understanding of the electronic transport processes occurring around the quantum point contact. Finally, we extend our model to account for the effects of quadrupolar splitting of nuclear levels and also depict the electronic transport signatures that arise from single and multi-photon processes.Comment: 21 pages, 8 figure

Stomach content analysis of the Indian mackerel Rastrelliger kanagurta (Cuvier) from Calicut, Kerala

The food and feeding of the Indian mackerel Rastrelliger kanagurta was studied from Calicut based on 1,551 fishes ranging in size from 100 to 280 mm total length (TL) collected from both multi-day trawlers and ring net during the period January to December 2006. There was a preponderance of empty stomachs in all the months. The dominant food item was copepod. Sand and foraminiferans also formed part of the stomach content. The fish, Bregmaceros sp. was noticed for the first time in the adult mackerel

Accurate estimation of low [< (10^-8) ohm . cm²] values of specific contact resistivity

Advancements in nanotechnology have created the need for efficient means of communication of electrical signals to nanostructures, which can be addressed using low resistance contacts. In order to study and estimate the resistance of such contacts or the resistance posed by the interface(s) in such contacts, accurate test structures and evaluation techniques need to be used. The resistance posed by an interface is quantified using its specific contact resistivity (SCR), and although multiple techniques have been utilized, inaccuracies of such techniques in measuring values of SCR lesser than ( < 10-8 Ω ldr cm2 ) have been reported. In this letter, an approach for estimating very low values of SCR (lower than the previously limiting ( < 10-8 Ω ldr cm2 )) using a cross Kelvin resistor test structure is demonstrated using aluminum to titanium silicide ohmic contacts, with a minimum estimated SCR value of 6.0 times 10-10 Ω ldr cm2

RF magnetron sputtered perovskite-oriented PSZT thin films on gold for piezoelectric and ferroelectric transducers

Conditions for depositing perovskite-oriented Pb0.92Sr0.08(Zr0.65Ti0.35) O-3 thin films on gold by RF magnetron sputtering are investigated. Deposition results were analysed by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffractometry. It was found that the desired perovskite phase can be obtained at a substrate temperature of 300 degrees C, much lower than the typically reported 650 degrees C for deposition on platinum

Nanoscale characterization of energy generation from piezoelectric thin films

We report on the use of nanoindentation to characterize in situ the voltage and current generation of piezoelectric thin films. This work presents the controlled observation of nanoscale piezoelectric voltage and current generation, allowing accurate quantification and mapping of force function variations. We characterize both continuous thin films and lithographically patterned nanoislands with constrained interaction area. The influence of size on energy generation parameters is reported, demonstrating that nanoislands can exhibit more effective current generation than continuous films. This quantitative finding suggests that further research into the impact of nanoscale patterning of piezoelectric thin films may yield an improved materials platform for integrated microscale energy scavenging systems