The development of a high sensitivity ac susceptometer and its application to the study of high temperature superconductors

The development of a high sensitivity ac susceptometer is outlined in this thesis. The intended use of this device is for the measurement of the magnetic field dependent penetration depth of high temperature superconductors in the Meissner state. The nature of the field depence may be useful in discerning the superconducting pairing state in these materials. Test measurements on the completed ac susceptometer show that its field dependent background is too large to extract any meaningful results from this experiment. However, the device has been used successfully to measure the temperature dependent penetration depth and the vortex melting transition of the high temperature superconductor YBa₂Cu₃O[sub 6.95].Science, Faculty ofPhysics and Astronomy, Department ofGraduat