Abstract:
Forsterite single crystals doped with vanadium were grown from melt using the Czochralski technique in various oxidation-reduction conditions: nitrogen, nitrogen with oxygen, argon, and argon with hydrogen atmospheres. The forsterite crystal/melt distribution coefficient is 0.07. Spectra of optical absorption within the range of 350-1600 nm, luminescence spectra, and the dependence of crystal density on vanadium content were studied. A thermodynamic analysis of the most probable oxidation state of vanadium together with a computer simulation of the forsterite crystal structure were also performed. A comprehensive study revealed that the forsterite crystals synthesized by the Czochralski technique mainly contain tetravalent vanadium, which substitutes for silicon. The oxidation state of this element can be changed to V3+ or V5+ by annealing the crystals under reducing or oxidizing conditions, respectively.
