  Quasicrystal approximant (CexY1-x)Cd6 (0 < x < 1) forms a network of
corner-sharing octahedra. We report that (Ce0.8Y0.2)Cd6 exhibits an anomalous
magnetic transition which can be classified neither into the conventional
static magnetic ordering nor into spin glasses. The anomalous transition is
characterized by the coexistence of a static order and a frequency-dependent
sharp positive anomaly in the 3rd-harmonic susceptibility. Based on the
investigation of the reference systems CeCd6 and (Ce0.05Y0.95)Cd6, we speculate
that the anomalous transition could be induced by disorder in the possible
frustrated Ce-network in the presence of the Kondo effect.
