The Effect of Heat Treatment on Crystal Structure in Zircon Monitored by ESR and XRD

AbstractX-band ESR spectra of zircon before and after heat treatment under oxygen rich atmosphere were measured with directions of the magnetic field applied in parallel and perpendicular to c-axis [001]. Seven peaks of Zeeman interaction were generated from the microwave energy absorptions due to the transitions between the spin states of natural impurity, gadolinium ions (Gd3+, S = 7/2). Angular variation of peak positions reflects that the symmetry surrounding of Gd3+ is D2d, signifying the replacement of Zr4+ by Gd3+ in the lattice. From XRD patterns, the unheated and after heated zircon are the same phase i.e. tetragonal phase of the space group I41/amd. The Rietveld refinement method was employed for derivation of the bond distance and bond angles of zirconium, silicon and oxygen atoms