  {\ss}-pyrochore KOs2O6, which shows superconductivity below ~ 9.7K, has been
converted into KxOs2O6 (x < 2/3 - 1/2) electrochemically to show spin
glass-like behavior below ~ 6.1K. Room temperature sample surface potential
versus charge transfer scan indicates that there are at least two two-phase
regions for x between 1 and 0.5. Rattling model of superconductivity for the
title compound has been examined using electrochemical potassium
de-intercalation. The significant reduction of superconducting volume fraction
due to minor potassium reduction suggests the importance of defect and phase
coherence in the rattling model. Magnetic susceptibility, resistivity, and
specific heat measurement results have been compared between the
superconducting and spin glass-like samples.
