Electron Paramagnetic and Nuclear Double Resonance ofF+Centers in BeO Single Crystals

Abstract

Single crystals of BeO which have been irradiated with neutrons show an EPR spectrum with partially resolved hyperfine structure. An ENDOR study of the hyperfine interaction leads to the conclusion that the spectrum arises from centers which consist of an electron trapped at an oxygen vacancy surrounded by four Be nuclei. The measured hyperfine interaction constants are: Ai/h= 10.3 MHz, A u/h= 16.4 MHz, and (e 2 qQ)/h= 1.1 MHz for the Be nuclei not on the c axis; and Ai/h = 4.2 MUz,A u /h = 9.2 MHz, and (e 2 qQ)/ h= 1.5 MHz for the nuclei along the c axis. These values lead to |^(fBe) | 2 =0.13X10 24 cm" 3 for the electron wave function at the c-axis nuclei, and |^(rBe) | 2 =0.06X10 24 cm -3 for the nonaxial nuclei. The measured g value for H parallel to the c axis is 2.0030.

Luminescence and defect centres in MgSrAl10O17:Sm3+ phosphor

“…25 Mg, 87 Sr and 27 Al have nuclear spins greater than 1/2 and it has not been possible to identify these nearby nuclei based on the present results. In an early ESR/ENDOR study of BeO single crystal, DuVarney et al [32] observed that the unpaired electron trapped at an anion vacancy (F + centre) interacts with four nearest-neighbor (nn) Be nuclei. In contrast to BeO, however, the hyperfine interaction in the present system is dipolar in nature with negligible isotropic component.…”

TL, OSL and ESR studies on beryllium oxide

“…c. Single crystals of BeO that were irradiated with neutrons showed an EPR spectrum with partially resolved hyperfine structure. An ENDOR study of the hyperfine interaction led to the conclusion that [12] the spectrum arose from a centre that consists of an electron trapped at an oxygen vacancy surrounded by four Be nuclei (i.e. F + centre).…”