Abstract
The formation mechanism of Cr4+ in PbWO4 (PWO) crystals is studied by optical absorption and X-ray excited luminescence (XEL) spectra. It is found that the concentration of Cr4+ depends not only on the initial amount of Cr3+ but more importantly on the coaddition of Nd3+. This material may be used as a new passive Q-switched laser in view of its high absorption coefficient in the NIR region. For Cr-containing sample, Cr3+ primarily replaces Pb2+ and results in large relaxation of lattice. In order to keep the scheelite structure, some Cr3+ ions are oxidized into Cr4+ and occupy W6+ sites. In the codoping case, Nd3+ preferentially substitute for Pb2+ and Cr is forced into W6+ sites in the form of Cr4+ to keep charge neutrality and structural integrity. This view is strongly supported by FT-IR spectra. The origin of the decrease and even extinction of XEL is also discussed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
