HRTEM studies of two new (Nd,Ca) sub x WO sub 3 bronzes synthesized under high pressure conditions

Two new (Nd,Ca) sub x WO sub 3 bronzes have been prepared by solid state reaction at P=50 kbar and T=1520K. The compounds were studied by x-ray powder diffraction and high resolution transmission electron microscopy. One phase was identified to be of hexagonal tungsten bronze type, while the other one was found to have the intergrowth tungsten bronze structure (2)-ITB. Disorder in terms of varying widths of the HTB and WO sub 3 slabs was sometimes observed. HTB tunnel rows terminating in the (2)-ITB structure were also seen. The neodymium and calcium contents in the two phases were confirmed by EDS analysis.