An electron spin resonance study of graphite irradiated with heavy ions

✍ Scribed by Y.P. Virmani; J.D. Zimbrick; E.J. Zeller

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 671 KB
• Volume: 10
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(72)90099-1

✦ Synopsis

Electron spin centers were produced in crystalline graphite samples irradiated with 1 MeV protons (p'), deuterons (d+) and helium ions (4He2+) at 77°K. Under these conditions, the linear energy transfer (LET) increased in the sequence p+ < d+ < 'He'+. The paramagnetic properties were studied by electron spin resonance (ESR) spectroscopy. Measurements of ESR line width as a function of radiation dose suggest that the centers are present in sufficiently high local concentrations to interact with each other. Measurements of ESR line widths and signal intensity as a function of sample temperature indicate that the spins produced by the radiation are of a localized nature as opposed to conduction type electrons in unirradiated graphite. These data also are consistent with the hypothesis that electrons are trapped at interstitial defect sites in the tracks left bv the bombarding particles.