First and foremost I thank my thesis supervisor Rob Kiefl for his contribution to the physics in this thesis, his support and encouragement, and the decisions made in the best interest of my career. Equal thanks to Jess Brewer who has been like a second supervisor and a fine promoter of the work that I've done.
Special thanks to Walter Hardy and Doug Bonn for many inspiring discussions and for being a continuous source of leading edge information. I thank the crystal growers Ruixing Liang and Joseph Brill whose samples made the experiments possible.
I am grateful to the following individuals for their helpful theoretical input during the years this work was conducted: Ian Affleck, Mohammed Amin, John Berlinsky, Marcel Franz, Alexander Golubov, Uwe Hartmann, Catherine Kallin, Alan MacDonald, Kazushige Machida, Philip Stamp and Alain Yaouanc. I also thank the Canadian Institute of Advanced Research for providing me with the opportunity to meet and collaborate with top level researchers in the field of superconductivity.
I thank the following for their assistance in performing the experiments which are presented in this thesis: Jacques Chakhalian, Kim Chow, Sarah Dunsiger, Tim Duty, Graeme Luke, Andrew MacFarlane, Roger Miller, Phillipe Mendels, Gerald Morris, David Noakes, Tanya Riseman, Carey Stronach and Morris White Jr. Special thanks to the TRIUMF technical staff for the many overtime hours devoted to building and assembling the experimental apparatus: Donald Arseneau, Curtis Ballard, Mel Good, Bassam Hitti, Keith Hoyle and Syd Kreitzman.
Finally, I thank Pauline who doesn't understand anything in this thesis, but has provided the loving support we all need in our lives.