Potassium tungsten bronze (KxWO3) may be prepared by hybrid microwave method using K2WO4, WO3 and W powder as raw materials. With the increase of nominal potassium content x, the crystal structure of KxWO3 transforms from hexagonal (0.20≤x≤0.33) to tetragonal (0.50≤x≤0.60). The tetragonal potassium tungsten bronze show metallic behavior. The hexagonal potassium tungsten bronze show semiconducting behavior and the charge density wave (CDW) transition is observed in K0.22WO3 around 265K. The KxWO3 has two types of crystal structure, hexagonal structure and tetragonal structure.
Tungsten bronze is widely applied in electrochromic devices and humidity sensors due to its special physical properties. Among them, some tungsten bronze materials have attracted much attention as they have the characteristic of superconductivity and show CDW phenomenon. KxWO3 is one of the tungsten bronze materials. The relationship between the resistivity of hexagonal single crystal KxWO3 and temperature was studied. It was found that with the decrease of temperature, samples with different potassium contents all showed CDW phenomenon, and the transition temperature of CDW (TCDW) depended more on x.
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