AN ELECTRON SPIN RESONANCE STUDY OF CHROMIUM, MANGANESE AND IRON IN SINGLE CRYSTALS OF LEAD FLUORIDE

Cr3+, Mn2+, Fe2+ and Fe3+ have been crystallized in PbF2 from the melt. A preponderance of Cr 3+ occupied substitutional sites with the excess positive charge compensated by an excess fluoride ion in the next-nearest-neighbour interstitial position, yielding the electron spin resonance characteristics g = 1·984±0·005 and fine splitting D = 0·334± 0·005 cm-1. Mn2+, for which g = 2·002±0·002 and 55A = 0·0090± 0·0002 cm-1, substitutionally replaced Pb2+. Poorly resolved 19F superhyperfine structure was detected. Fe2+, Fe3+ and Li+ produced broad electron spin resonance signals and it was concluded that these ions induced conduction centres in the crystal.