The Electron Paramagnetic Resonance of Fe3+ Observed in Two Axial Sites in Synthetic Single Crystals of Zircon (ZrSiO4)

Abstract

The electron paramagnetic resonance of synthetic zircon single crystals doped with iron is reported confirming the observations of two different spectra made in natural samples previously. The spin‐Hamiltonian parameters have been established by careful measurement of the angular variation of the two axial spectra at X‐band at room and nitrogen temperatures, and computer fitting the observed line positions with those calculated from diagonalising the appropriate spin‐Hamiltonian.

EPR study of radiation-induced defects in the thermoluminescence dating medium zircon (ZrSiO4)

“…In annealed zircon samples the EPR signal of the paramagnetic defect associated with Tb 4+ cannot be observed, suggesting that the terbium ions are all in the trivalent state. After exposure to ionizing radiation we observe an EPR pattern, which is due to Tb 4+ ; this conclusion is drawn on the basis of the positions of the EPR spectrum and from the fact that the four-lines hyperfine structure including the observed splitting is typical for the interaction of the 4f 7 electron system with the 159 Tb nucleus. It should be noted here that the results for Tb and Dy are consistent, because in both cases it appears, that in non-irradiated or annealed zircon samples these impurities are in the trivalent state.…”

“…Tb 4+ . The electronic configuration 4f 7 and the corresponding ground state 8 S 7/2 of the rareearth ions Tb 4+ , Gd 3+ , and Eu 2+ are easily observed by means of EPR. These high-spin state ions are perfect probes for the investigation of crystal fields (i.e.…”

“…The Gd 3+ ion was the first rare-earth ion to be studied in zircons by means of magnetic resonance [3]. The incorporation of impurities in natural and artificially grown zircon crystals has been studied in the following papers: Er 3+ [4,5] and Dy 3+ [4]; Nd 3+ and Yb 3+ [6]; Fe 3+ [7]; Ti 3+ [8,9]; Mn 2+ [5]; V 4+ [10,11]; Mo 5+ [12,13]; SiO n− m centres [5,[13][14][15]; and besides the ones mentioned here, there have been many other publications in this area.…”