Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 17 of 17 for “"perpendicular magnetic field"”.
-
Quantised charge pumping in a perpendicular magnetic field
… GaAs/ AlGaAs electron pump in the presence of a perpendicular magnetic field are documented in detail in this thesis. Perhaps the most important observation is an enhancement of the quantisation as a result of the applied field. To determine the accuracy of the quantisation we applied novel …
-
Thermal conductivity of superconducting alloy films in a perpendicular magnetic field
… of superconducting films of In - Bi alloys in a perpendicular magnetic field. The films were quench-condensed onto glass substrates held at 77 K, and had thicknesses ranging from l050 to 4570 A. The ratios of the BCS coherence length to the electron mean free path for these films were in the …
-
Implementation of the Quantum Hall Effect based precision resistance measurement system
… electron gas (2DEG) is subjected to a strong perpendicular magnetic field and when the system is cooled to low temperatures. The QHE harbours a wealth of unique phenomena. Of interest is the existence of the Quantum Hall Resistance (QHR) which had found to be related to two fundamental …
-
Insulator -Superconductor Transitions in Two Dimensions
… behavior near the 2D IST in the presence of a perpendicular magnetic field. We show that with increasing field H, the QD and QC regimes, in which vortex degrees of freedom are suppressed, crossover to a new magnetically activated (MA) regime, where the correlation length xi ∼ 1/ H . In this …
-
Characterization of the magnetoresistance of polypyrrole
… such as for use as motor windings or as magnetic field sensors, require a precise knowledge of the electrical properties of the polymers being used. This thesis presents a study of the magnetoresistance of the conducting polymer polypyrrole. It was found that the electrical resistance of …
-
Electronic properties of bilayer graphene in a steady magnetic field
… of bilayer graphene in a steady, parallel magnetic field. Using the tight–binding model, and taking into account relevant tight–binding parameters, we find a new contribution to the electronic Hamiltonian describing the orbital effect of the magnetic field. We consider the effect of the …
-
Vortex distributions and dynamics in superconductors near surface steps and sample edges studied by scanning SQUID microscopy and critical current measurements
… into the superconducting state in an applied magnetic field. The edge of a sample acts as a barrier to vortex entry into the superconductor and can have a substantial effect on the transport properties of vortices. We have used a Scanning SQUID Microscope (SSM) to directly image the vortex …
-
Interaction effects and disorder in two-dimensional electron systems
… as a function of electron density when a strong perpendicular magnetic field is applied. A strongly amplified pick-up of the Shubnikov-de Haas oscillation and a modification of t he quantum Hall effect are reported in chapter 8. Furthermore, a new technique for measuring the electron density in …
-
Insulator-Superconductor Transitions in Two Dimensions
… behavior near the 2D IST in the presence of a perpendicular magnetic field. We show that with increasing field H, the QD and QC regimes, in which vortex degrees of freedom are suppressed, crossover to a new magnetically activated (MA) regime, where the correlation length ξ ~ 1/√H. In this …
-
Study of magnetohydrodynamic effects for the Richtmyer-Meshkov instability
… to capture qualitative images of the plasma flow field and are ready for use in future hydrodynamic experiments where the qualitative growth is of interest. Simulations utilized the hydrocode FLAG, developed at Los Alamos National Laboratory, are performed on a 2D shock cylinder plasma-air …
-
Transport And Optical Properties Of Low-Dimensional Complex Systems
… potential in the presence of a uniform perpendicular magnetic field. We clearly demonstrate the quantum fractal nature of the energy bands at reasonably low magnetic fields. We present results for the energy bands as functions of both wave number and magnetic flux through the unit cells …
-
Magnetic Skyrmions in Multilayers with Interfacial Dzyaloshinskii-Moriya Interactions
<p>Magnetic skyrmions, topologically stable spin textures that can be driven by electric currents efficiently, have both rich physics and potential applications in future technology such as spintronic devices for data storage. Magnetic skyrmions in multilayers with interfacial Dzyaloshinskii-Moriya …
-
Charging of small two-dimensional electron puddles
… sign of repelling each other Application of high perpendicular magnetic field increases n0 , creating a sharp boundary between periodic and "paired" parts of the addition spectrum Previously, we hypothesized that disorder and electron interactions within the low-density dot split it into two …
-
Electrical injection and detection of spin polarization in InSb/ferromagnet nanostructures
… and strong spin-orbit interaction. Using ferromagnetic CoFe, lateral InSb/CoFe devices are fabricated by semiconductor processing techniques. The saturation magnetizations of various CoFe electrodes with different widths are calculated from Hall measurements in which the fringing fields of the …
-
Elektrischer Transport in GaN- und InN-Nanodrähten
… doping concentration inside those wires without field effect measurements and contact resistance has been developed. The defect structure inside those wires has been analysed with the help of spectral photoluminescence measurements. Here several defect bands have been found and it was possible …
-
Probing Symmetry and Disorder Effects in the Fractional Quantum Hall States of the Second Landau Level
… cryogenic temperatures, and placed in a strong perpendicular magnetic field exhibit a set of ground states referred to as the fractional quantum Hall states (FQHS). The FQHSs forming in the region called the second Landau level are some of the most exciting states as several theories predict …
-
Investigation on High-Mobility Graphene Hexagon Boron Nitride Heterostructure Nano-Devices Using Low Temperature Scanning Probe Microscopy
… by hexagonal boron nitride and in a weak perpendicular magnetic field. We employ a magnetic focusing transport configuration to image carriers that emerge ballistically from an injector, follow a cyclotron path due to the Lorentz force from an applied magnetic field, and land on an …