DIAMAGNETISM DUE TO FLUCTUATIONS IN SUPERCONDUCTORS.
HARVARD UNIV CAMBRIDGE MASS DIV OF ENGINEERING AND APPLIED PHYSICS
Pagination or Media Count:
Fluctuations of the order parameter above T sub c in superconductors give rise to a small diamagnetism, comparable in magnitude to the Landau diamagnetism. An extremely sensitive magnetometer system was devised to measure this small temperature-dependent diamagnetism. A superconducting quantum interference device coupled to the sample was used as a magnetic flux detector. The sample temperature could be varied continusously between 2 K and 16 K while magnetization changes as small as 10 to the - 8th power gauss were resolved. Extensive measurements have been performed on bulk single crystals of three materials indium, lead, and type II lead-thallium alloys. Each of these materials shows a temperature-dependent diamagnetism which is qualitatively described by Pranges calculation for small applied fields. Results are discussed.
- Electricity and Magnetism