Some Surprises in Superconductivity

Abstract

Many times in the recent past-also here-I have pointed out how superconductivity and magnetism are very closely related. Bill McCallum, who works with Brian Maple in La Jolla, has now done some measurements which show for the first time both phenomena in the very same crystal; one clean cut crystal which is no longer a mixture of compounds. This is only one of the various surprises. You will hear about it for the next seven minutes, as I want Bill Mc-Callum to speak. [See McCallum's paper-this Conference Proceedings]. This morning I wasn't asleep when Varma mentioned the e/a ratio. The reason why I didn't want to say anything was because there were so many comments anyhow, and I was just too depressed for the following reason. Once upon a time, the electron per atom ratio (e/a) as a criterion for transition temperatures, worked beautifully. Well, it doesn't work so well any longer.