XPS characterization of YAlO3:Co single crystals
|Ewa Talik 1, Magdalena M. Kruczek 1,2, Halina Sakowska 2, Wlodzimierz Szyrski 2|
1. University of Silesia, August Chełkowski Institute of Physics, Department of Solid State Physics, Uniwersytecka 4, Katowice 40-007, Poland
The perovskite-like yttrium aluminate YAlO3 (orthorhombic structure) reveals a polarized laser beam and because of it, is an excellent host for solid state lasers scintillators and acustooptic materials as well as Q-switch.
Comparing with YAG, the single crystals of YAP can be grown faster, have a smaller core and more favorable distribution coefficient for rare-earth dopants; it seems to be useful for laser host.
The YAP:Co single crystals were grown by the Czochralski method using iridium crucibles (54 mm in diameter and 52 mm in height) and iridium afterheater. Oxypuller 05-03 equipment made by Cyberstar (France) was used. As raw materials: Y2O3 (5N), Al2O3 (5N) and CoO + Co2O3 (4.85N) were used. The concentration of Co2+ ions was 0.22 at. %, 0.30 at. %, and 0.40 at. %. The crystals were grown under N2 atmosphere with a gas flow rate of 0.4 l/min. The pulling rate was between 1 - 2 mm/h and the rotation rate was between 10 rpm and 20 rpm. An automatic diameter control was carried out using Cyberstar programme, in which weight differential was maintained constant. Sartorius balance was used to control the weight of the growing crystal.
The obtained single crystals up to 25 mm in diameter and 60 mm in length were free of macroscopic defects and inclusions of other phases.
The samples for measurements were taken from each crystal by slicing for a wafer ~1mm thickness, and double sides polishing. A part of this wafers were annealed in reduction atmospheres:
After annealing the wafers were slowly cooled down to room temperature.
The electron spectroscopy XPS shows the chemical composition is in agreement with a nominal composition of compound. A very low contamination of carbon was detected. The narrowest core level lines were observed for the sample annealed in hydrogen which was colourless.
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Presentation: Poster at Joint Fith International Conference on Solid State Crystals & Eighth Polish Conference on Crystal Growth, by Ewa Talik
See On-line Journal of Joint Fith International Conference on Solid State Crystals & Eighth Polish Conference on Crystal Growth
Submitted: 2007-01-15 10:50 Revised: 2009-06-07 00:44