Journal Article

PUBDB-2018-00323

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Structure and thermal expansion of $\mathrm{Ca_{9}Gd(VO_{4})_{7}}$: A combined powder-diffraction and dilatometric study of a Czochralski-grown crystal

Paszkowicz, W. (Corresponding author) ; Shekhovtsov, A. ; Kosmyna, M. ; Loiko, P. ; Vilejshikova, E. ; Minikayev, R. ; Romanowski, P. ; Wierzchowski, W. ; Wieteska, K. ; Paulmann, C.DESY* ; Bryleva, E. ; Belikov, K. ; Fitch, A.

2017
Elsevier Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.nimb.2017.07.026

Abstract: Materials of the Ca$_9$RE(VO$_4$)$_7$ (CRVO) formula (RE = rare earth) and whitlockite-related structures are considered for applications in optoelectronics, e.g., in white-light emitting diodes and lasers. In the CRVO structure, the RE atoms are known to share the site occupation with Ca atoms at two or three among four Ca sites, with partial occupancy values depending on the choice of the RE atom. In this work, the structure and quality of a Czochralski-grown crystal of this family, Ca$_9$Gd(VO$_4$)$_7$ (CGVO), are studied using X-ray diffraction methods. The room-temperature structure is refined using the powder diffraction data collected at a high-resolution synchrotron beamline ID22 (ESRF, Grenoble); for comparison purposes, a laboratory diffraction pattern was collected and analyzed, as well. The site occupancies are discussed on the basis of comparison with literature data of isostructural synthetic crystals of the CRVO series. The results confirm the previously reported site-occupation scheme and indicate a tendency of the CGVO compound to adopt a Gd-deficient composition. Moreover, the thermal expansion coefficient is determined for CGVO as a function of temperature in the 302–1023 K range using laboratory diffraction data. Additionally, for CGVO and six other single crystals of the same family, thermal expansion is studied in the 298–473 K range, using the dilatometric data. The magnitude and anisotropy of thermal expansion, being of importance for laser applications, are discussed for these materials.

Note: (c) Elsevier B.V. ; Post referee fulltext in progress; Embargo 12 months from publication

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Contributing Institute(s):

1. PETRA III Extension (FS-PEX)

Research Program(s):

1. 6213 - Materials and Processes for Energy and Transport Technologies (POF3-621) (POF3-621)

Experiment(s):

1. DORIS Beamline F1 (DORIS III)

Appears in the scientific report 2017

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Database coverage:
; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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