Study of the Intermediate State in Superconductors using Cerium Phosphate Glass

The Faraday effect in glasses containing cerium metaphosphate is used to resolve the intermediate state in various superconducting metals. Photographs of approximately 0.25mm thick glass at the sunface of the metal with a transverse magnetic field are given for the following conditions and metals: (1) the magnetic field is less than H/sub c/, the critical field (tantalum), and (2) the magnetic field is more than H/sub c/ and is then decreased to a value considerably below H/sub c/ (tin). Patterns of normal and superconducting domains appear on the photographs. Possibilities of the application of similar glasses to the study of superconductors are pointed out. e.g., in motion pictures to record kinetic details like wall motions and annealing behavior of frozen-in flux. (D.L.C.)