Magnetic studies of oxidized impurities in pure copper using a SQUID system

Abstract
A magnetometer system utilizing a SQUID and a superconducting flux transformer has been used to monitor the internal oxidation process in very pure copper. Both remanent moment and low field susceptibility have been measured for copper containing 0.1-1 at ppm Fe and 70 at ppm Fe in various states of anneal. The results suggest that the oxidation process proceeds quite differently in the previously unobserved situation where very dilute amounts of iron are present than in the case of relatively high impurity concentrations.
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