The resistivity, Seebeck coefficient, Hall coefficient, and superconducting transition temperature have been measured in ${\mathrm{K}}_x$ W${\mathrm{O}}_3$ for $0.20<~x<~0.32$ over the temperature rangee 1.5 to 375 K. The normal-state transport properties show temperature- and composition-dependent anomalies qualitatively similar to those observed in ${\mathrm{Rb}}_x$ W${\mathrm{O}}_3$, except that they occur at higher temperatures. This critical temperature has the same dependence on composition as observed in ${\mathrm{Rb}}_x$ W${\mathrm{O}}_3$. This behavior is in contrast to that of ${\mathrm{Cs}}_x$ W${\mathrm{O}}_3$ in which no anomalies are observed. The superconducting transition temperature also has the same general dependence on composition as in ${\mathrm{Rb}}_x$ W${\mathrm{O}}_3$, except it is lower for any given $x$ value rising slowly as $x$ decreases below 0.32, dropping to a minimum near $x=0.25\mathrm{}$, then increasing again as $x$ decreases below 0.25.

• Received 11 August 1980

DOI:https://doi.org/10.1103/PhysRevB.23.2219