Paramagnetic Ge–Li centres in alpha quartz revisited: The DLi([GeO4/Li]0D) centre

Abstract

A previously unreported stable paramagnetic defect centre in single-crystal alpha-quartz has been studied by quantitative X-band electron paramagnetic resonance spectroscopy at 15, 100, and 296 K, and is shown to contain a Ge3+ ion, presumably located substitutional for Si4+, with a nearby interstitial Li+ ion. The centre, called DLi herein, grows in slowly (months) after room-temperature x-irradiation and storage. Hyperfine structure arising from 73Ge, 7Li, and 29Si has been observed. The spin-Hamiltonian parameter matrices g, A(7Li), A(73Ge), and P(73Ge) are reported, also for centre CLi. A thermal dynamic process, probably involving Li+ hopping, begins to be appreciable above 100 K. Discussion of DLi, its apparent growth from another paramagnetic centre (not yet fully characterized), and comparison with other similar defects is included.PACS Nos.: 42.70.Ce, 61.72.Hh, 61.72–y, 61.72S–, 61.72uf, 61.80–x, 76.30–v, 76.30.Mi