Accession Number:

ADP011875

Title:

Chromium Recharging Processes in the Y3Al5O12: Mg, Cr Single Crystal under the Reducing and Oxidizing Annealing Influence

Descriptive Note:

Conference proceedings

Corporate Author:

NATIONAL UNIV LVIV (UKRAINE)

Report Date:

2001-01-01

Pagination or Media Count:

6.0

Abstract:

The influence of reducing and oxidizing annealing on optical absorption spectra of the yttrium aluminium garnet YAG single crystal co-doped with Mg and Cr is investigated using step-by-step isothermal and isochronous thermal treatment in H2 or air flow. The changes in the spectra were analyzed using decomposition on elementary absorption bands of Gaussian shape. The separated absorption bands attributed to the Cr4 ions occupying octahedral and tetrahedral sites in garnet lattice demonstrate different behaviour. The analysis allows to distinguish the electronic recharging process Cr4sub OCT left right arrow Cr3sub OCT taking place in the octahedral sites of garnet lattice and having lower activation energy from the chromium migration process Cr4sub TETR left right arrow Cr4sub OCT happening at higher temperatures or longer exposure. Estimations show that approximately 0.2 of total number of chromium ions occupied tetrahedral sites forming phototropic centers in the YAG Mg, Cr crystal.

Subject Categories:

  • Inorganic Chemistry
  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE