Contents

• Contents
• List of Tables
• List of Figures
• Introduction
• Theory
  • Magnetic Properties of Conventional Superconductors
    • Type-I Superconductors
    • The London Penetration Depth
    • The Coherence Length (Pippard's Equation)
    • Ginzburg-Landau Theory
    • The Clean and Dirty Limits
    • BCS Theory for Conventional Superconductors
    • Type-II Superconductors and the Vortex State
  • The Pairing Mechanism
    • s-Wave Pairing
    • The Motivation for an Alternative Pairing Mechanism
    • d-Wave Pairing
  • Anisotropy in $\mbox{YBa$_{2}$ Cu$_{3}$ O$_{7- \delta}$ }$
    • General Considerations
    • Anisotropy of the Magnetic Penetration Depth
    • Anisotropy of the Energy Gap
• Measuring the penetration depth with TF-$\mu ^{+}$SR
  • The Field Distribution
  • The Role of the Positive Muon
  • The Raw Asymmetry For 2-Counter Geometry
  • The Corrected Asymmetry
  • The Relaxation Function
  • Modelling The Asymmetry Spectrum of the Vortex State
  • 4-Counter Geometry and the Complex Polarization
  • The Rotating Reference Frame
• Experimental Determination of $\lambda _{ab} (T)$
  • Sample Characteristics
  • The Apparatus
  • The Measured Asymmetry
  • Data Analysis
• Experimental Determination of $\lambda _{ab} (T)$
  • Sample Characteristics
  • The Apparatus
  • The Measured Asymmetry
  • Data Analysis
• Conclusion
• Bibliography
• Some Remarks About The Fitting Program