Anomalous electrical resistivity of Al 2O 3 single crystal degraded by electron irradiation

Radiation-induced electrical degradation was investigated in single-crystal alumina under 2.2 MeV electron irradiation representing an ionizing dose rate of 5.7 × 10 ³ Gy/s and an electrical field of 1.6 × 10 ⁵ V/m at 773 K. After irradiation with a dose to 2.9 × 10 ⁸ Gy, electrical resistivity both on the surface and in the bulk decreased in the temperature range of 300 to 773 K. Substantial resistivity also decreased from its initial value due to the irradiation; the degradation ratio was much smaller than the case of polycrystalline speciments. On the other hand, surface resistivity decreased with increasing measurement temperature, with an abrupt change by 4 orders of magnitude around 600 K, and showed thermal hysteresis.