Electrical resistivity is an important indicator of metal thin film quality. In this study, the influence of argon working pressure on the properties of metal thin films was evaluated, and the thickness effect on the resistivity of metal thin films was investigated. The sputtered thin film resistivity performances of seven metals as a function of argon pressure were measured, and the results turned out that the argon pressure was vital to film quality. Further investigation on sputtered chromium thin films using XRD, SEM and XPS revealed that the argon pressure influences the microstructure of sputtered metal thin films. Different microstructure is the reason for different resistivity performances, and John Thornton's "Zone Model" explains all these behaviours well. The resistivity of aluminum and chromium thin films with thickness from 15 to 150 nm were compared, the resistivity change significantly. The scaling trends are different for different metals. / Materials Engineering

Resistivity and photoconductivity measurements have been made, using hydrostatic pressures up to 75 kb on localised states in some III - V semiconductors, including ones with transition metal ions present. The systems investigated were GaAs: Sn, GaAs: Cr: S, n - In[x] G[1-x] As[y] P[1-y], InP: Fe and GaAs: Cr. Many electronic transitions involving localised states (some deep in the band gap) appear to have anomolously high pressure coefficients. Possible explanations are discussed.

<p> Recrystallization of aluminum alloys, which affects their mechanical properties, was examined by a variety of experimental techniques with electrical resistivity (ER) measurements being one of them. In this work, a new method based on in-situ electrical resistivity measurements has been originated and employed for characterization of recrystallization. In contrast to traditional method of resistivity measurements at either room or liquid N2 temperature on isothermally/isochronally heat-treated samples, a new and simpler approach was proposed. In this work, resistivity of a long sample with a small cross section area (usually, 70 x 2 x 0.2 mm3 strips were employed) was continuously measured while the sample was heated from room temperature to 400°C. In this case, there are several independent contributions to electrical resistivity including contributions from lattice vibrations, second-phase particles, presence of solutes and defects, etc. </p> <p> In order to separate precipitation and recrystallization, a new annealing cycle was proposed through thermodynamic modeling. It was demonstrated that for 5xxx AI alloys only contributions from phonons, Pr, and dislocations, pd, were important. By analyzing a temperature dependence of p , it was intended to separate the effect related to a dislocation density, i.e. to a degree of recrystallization. Since Pr >> pd, this effect is elusive. It can only be detected if a robust numerical differentiation is utilized. A novel spline-based method of robust numerical differentiation was developed and employed to reveal these elusive effects from p(T) (or R(T)) profiles. It was shown that a characteristic peak of the d p (T) / dT curves points to onset and end of "events" taking place in AI alloys and that peaks' positions depend on the degree of deformation and amount of alloying additions such as Fe and Mn. The onset and extent of recrystallization seen in the resistivity measurement experiments were confirmed by optical metallography and hardness measurements. Uniformity of deformation in samples was investigated by micro-hardness measurements followed by a detailed statistical analysis to prove that deformation is uniform throughout cross-section of the materials. </p> <p> Results suggested that increasing degree of deformation and alloying additions (Fe and Mn) lower the temperature of onset of recrystallization. In addition, it was observed that kinetics of recrystallization was accelerated by the increasing degree of deformation and alloying additions whereas recrystallized grain size decreases with increasing additions of Fe and Mn in Al-3% Mg alloys. </p> / Thesis / Master of Applied Science (MASc)

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The purpose of this investigation was to study some of the transport effects in a single crystal of arsenic at liquid helium temperatures in a magnetic field up to twenty-four kilogauss. The experimental coefficients determined were the isothermal magnetoresistivity and the isothermal Hall resistivity.

DC electrical surveying involves the injection of current into the earth, and the measurement of the electrical potential differences this produces. A number of electrode configurations such as the Schlumberger and Wenner arrays, dipole-dipole and pole-pole geometries are in common use for electrical surveying. New acquisition systems enable the convenient collection of data with a number of common configurations at the same time. It is found however that while the recovery of layered structure from electrical surveys can be effective, the sensitivity and resolving power of such systems in detecting the presence of anomalous three-dimensional (3-D) bodies is poor. This is mainly due to the dominance of conduction pathways through the layered earth compared to the influence of small 3-D conductivity anomalies.Theoretical relationships between the responses of various survey geometries to the layered earth may be established as is shown in this thesis, but their response to 3-D targets differs strongly. This thesis introduces a new procedure for anomalous target detection by the computation of an apparent resistivity residual using multi-electrode configuration survey data. This procedure, applicable to a variety of electrode geometries, reduces the dominance of the layered earth response and enhances the signal from 3-D structures.In the development and testing of this new apparent resistivity residual, numerically modelled data were used. In order to obtain suitable test data of high accuracy it was necessary to make improvements to modelling software. For this purpose, recently developed techniques in numerical modelling such as the biconjugate gradient method, new digital linear filters for computation of Hankel transforms, and spectral formalism were employed in an integral equation approach for the software developed in this thesis.The computed apparent ++ / resistivity residual was found to depend on the array type and dimensions, the nature of the anomalous zone, geological layer geometries, and resistivity contrasts of the layers involved. While the apparent resistivity residual signature requires some measure of interpretation, it is shown to enhance the resolution and detectability of 3-D targets in a layered environment.The presence of random noise produces some degradation in the performance of the residual technique, but a normalisation procedure has been developed to alleviate the problem. A preliminary field trial showed that survey profiles of apparent resistivity residual were able to locate a subsurface conductive anomaly in an area in Western Australia.A transitional zone is defined as a layer in the earth where resistivity varies as a continuous function of depth. A theoretical formulation for the electrical response of an earth structure composed of anomalous 3-D bodies in the presence of transitional layers is introduced. Tests on synthetic survey data showed that the apparent resistivity residual is an effective anomaly detector in transitional layer environments.A multi-system method of computing an apparent resistivity residual has been developed theoretically and tested on both synthetic and field data. This new approach when applied to resistivity profiling is more sensitive to, and gives greater resolution of, localised anomalies than is possible using conventional profiling procedures.