EPR of silica and fluoride glasses implanted with titanium and zirconium

Silica substrates were implanted with Ti+ ions to nominal doses (D) ranging from 5 x 10(16) to 6 x 10(17) ions/cm(2) at an energy of E = 160 keV. The lines of electron paramagnetic resonance (EPR) with g = 1.938 to 1.944 are attributed to Ti3+ with ground state \xy) located in tetragonally compressed oxygen octahedron. Computed spectra of some samples implanted with Ti, besides the line at g = 1.94, contain two isotropic lines with (g = 1.968 and g = 1.972) which are assigned to Ti3+ ions entering clusters or compounds of titanium with silicon or oxygen. The greater fraction of implanted Ti exists in non-paramagnetic states. In silica glass implanted with Zr+ (E = 195 keV, D = 5 x 10(16) and 10(17) ions/cm(2)) Zr3+ ions in the amount of 0.5-1% of implanted Zr are in distorted octahedral environment producing an asymmetric line with g similar to 1.916 and width similar to 14 mT. For fluoroaluminate glass (FAG) implanted with Ti+ (E = 150 keV, D = 2 x 10(16) 5 x 10(16) and 10(17) cm(-2)) EPR line at g = 1.944 and optical absorption band at similar to475 nm similar to those observed earlier for FAG doped with TiO2 were assigned to Ti3+ ions in tetragonally compressed octahedron. In the EPR spectra of FAG coimplanted with Ti+ (E = 150 keV) and F+ (E = 90 keV) the triplet centered at g = 1.9375 with ratio of intensities of components equal to 1:2:1 and the separation between adjacent components equal to 1.1 mT was observed and attributed to TiF2+ molecular ions. The integrated intensity of this triplet in relation to that of the g similar to 1.94 single line varies from 0.6% to 2% depending on F+ dose. The decrease in the content of Ti3+ ions with increasing implantation dose is interpreted in terms of chemical sputtering of Ti-F molecules. The g-values of Zr3+ ions incorporated into fluorozirconate glass (FZG) after the implantation of Zr+ ions differ from those obtained earlier for F-center near Zr4+ in X- or gamma-ray irradiated FZG. We conclude that some part of the implanted zirconium is incorporated into FZG as Zr3+ in distorted octahedral environment. Structural defects produced in silica and fluoride glasses by Ti, and Zr+-ion implantation are not discussed. (C) 2002 Elsevier Science B.V. All rights reserved.