EPR OBSERVATION OF CU2-CU2+ PAIRS IN CUPRIC OXIDE POWDERS()

We report the observation of an EPR spectrum attributable to Cu2+-Cu2 pairs with resultant electronic spin S = 1, from cupric oxide anneale d in the temperature range from 700 to 900-degrees-C. The spectrum con sists of only a single line at g = 3.12 with seven hyperfine component s. From the weight loss and oxygen content measurements, it was found that the observation of such a signal strongly depends on the oxygen c ontent of the sample.