Phys. Status Solidi B, 2100395 (2021)
A. Setzer, P.D. Esquinazi, O. Daikos, T. Scherzer, A. Pöppl, R. Staacke, T. Lühmann, S. Pezzagna, W. Knolle, S. Buga, B. Abel, and J. Meijer
Several diamond bulk crystals with a concentration of electrically neutral single substitutional nitrogen atoms of ≤ 80 ppm, the so-called C or P1 centers, are irradiated with electrons at 10 MeV energy and low fluence. The results show a complete suppression of the irreversible behavior in field and temperature of the magnetization below 30 K, after a decrease in ≤ 40 ppm in the concentration of C centers produced by the electron irradiation. This result indicates that magnetic C centers are at the origin of the large hysteretic behavior found recently in nitrogen-doped diamond crystals. This is remarkable because of the relatively low density of C centers, stressing the extraordinary role of the C centers in triggering those phenomena in diamond at relatively high temperatures. After annealing the samples at high temperatures in vacuum, the hysteretic behavior is partially recovered.