First observation of Ce volume collapse in CeN

Abstract

On the occasion of the 80th anniversary of the first observation of Ce volume collapse in CeN a remembrance of the implications of that transcendent event is presented, along with a review of the knowledge of Ce physical properties available at that time. Coincident anniversary corresponds to the first proposal for Ce as a mix valence element, motivating to briefly review how the valence instability of Ce was investigated since that time.