Hon. B.Sc. - University of Western Ontario - 1991
M.Sc. - University of British Columbia - 1994
Department of Physics and Astronomy
A strong linear temperature dependence for was found to exist below 50K for applied magnetic fields of 0.5T and 1.5T. This linear temperature dependence contradicts the consensus of previous SR studies which suggested a behaviour consistent with conventional s-wave pairing of carriers in the superconducting state. The presence of a linear term in the data reported here, supports recent microwave cavity measurements in zero field and indicates the existence of a more unconventional pairing state. In addition, a possible field dependence for at low temperatures was indicated by the data, with having a range of 1347 - 1451Å and 1437 - 1496Å for the 0.5T and 1.5T data, respectively. The range of these values was determined by fitting the data several different ways. For each type of analysis, was found to be greater and the linear term was stronger in the 0.5T data. Furthermore, the 1.5T data appear to agree better with the microwave cavity measurements.
Included in this thesis is a qualitative description of the conventional
s-wave pairing state and a proposed d-wave pairing state,
dx2-y2. The findings in this SR study
support the latter, but does not rule out the possibility of other
anisotropic pairing states or isotropic pairing theories in which
critical fluctuations persist down to very low temperatures.