Sodium gadolinium tungstate NaGd(WO4)2:: Growth, crystallography, and some physical properties

Pure, and Nd3+ -doped NaGd(WO4)(2) (NGW) single crystals, up to similar to 85 mm long and similar to 30mm in diameter, have been grown using the Czochralski method. The Nd3+ segregation coefficient for growth along the [100] direction was 1.3 +/- 0.025. X-ray diffraction at room temperature established the lattice constants as: a = 5.2483(2) angstrom and c = 11.392(2) angstrom, for the tetragonal scheelite-like structure (space group 141/a), with two formula units in the unit cell. Inter-atomic distances and bond angles are also given. The thermal expansion coefficients were a,= 11.6 x 10(-6) /degrees C and a(c) = 23.3 X 10(-6) /degrees C, in the a and c directions, respectively. The Nd3+ absorption spectrum at around 800 nm for E-Le polarization was measured with high resolution, providing a peak absorption cross-section of 2.6 x 10(-20) cm(2) at 800.8 nm. (C) 2007 Published by Elsevier B.V.