The binary system ZnONb2O5

An Unexpected Crystal‐Chemical Principle for the Pyrochlore Structure

“…The previously reported binary phase equilibria for the perimeter systems (Bi 2 O 3 -Nb 2 O 5 , [48][49][50] Bi 2 O 3 -ZnO, [51] ZnO-Nb 2 O 5 [52,53] ) were confirmed in the present study, with the exception of the Bi 2 O 3 -Nb 2 O 5 system above 0.75 Bi 2 O 3 (represented here as a solid solution extending to Bi 2 O 3 ) which we did not investigate in detail. This region apparently forms a series of modulated fluorite superstructures; [49] differences in the reported diagrams likely arise from variations in cooling methods and whether specimens were examined by Xray or electron diffraction methods.…”

Single-Crystal Growth of ZnO:Ga by the Traveling-Solvent Floating-Zone Method

“…We described the growth process in Experimental Procedures. For the flux selection, we considered the following solvents: V 2 O 5 –ZnO, B 2 O 3 –ZnO, P 2 O 5 –ZnO, MoO 3 –ZnO, WO 3 –ZnO, and Nb 2 O 5 –ZnO. , Because they are oxides that lower the melting point below 1300 °C. Growth attempts using V 2 O 5 -, WO 3 -, and P 2 O 5 -based solvents failed due to severe penetration and solvent volatility.…”

“…The high-temperature gradient near the solid–liquid interface increases significantly the crystallization driving force and Ga 2 O 3 doping amount. We selected a new oxide mixture 67.7 atom % (ZnO) + 9.3 atom % (B 2 O 3 ) + 16.3 atom % (MoO 3 ) + 6.7 atom % (Nb 2 O 5 ) as a solvent based on the analysis of phase diagrams of ZnO-B 2 O 3 , ZnO-MoO 3 and ZnO-Nb 2 O 5 , systems, which reduced the growth temperature to below 1300 °C in which ZnO or GZO started to evaporate, suppressed the characterization of strong polarity crystallization based on ZnO materials, and successfully grew a series of ZnO: x wt % Ga 2 O 3 ( x = 0–1) (hereafter GZO- x wt %) single crystals with high quality and of centimeter size. The actual Ga 2 O 3 doping amount reached 0.7 wt %, which is much higher than 0.053 wt % of GZO crystals grown by the hydrothermal method .…”

Influence of Copper(II) Oxide Additions to Zinc Niobate Microwave Ceramics on Sintering Temperature and Dielectric Properties

“…The melting points of ZnNb 2 O 6 and CuO are 1405°and 1326°C, respectively. 16,17 From these results, it can be postulated that a CuO-rich liquid phase is formed at ϳ800°C and is subsequently recrystallized during cooling. 11 Figure 5 shows XRD patterns of specimens sintered at 925°C for 2 h as a function of CuO content from 0 to 9 wt%.…”