  Two correlated superconducting phases are identified in layered
superconductor BaTi2(Sb1-xBix)2O (x=0.16), with the superconducting transition
temperatures of TC = 6 K (the high TC phase) and 3.4 K (the low TC Phase),
respectively. The 6 K superconducting phase appears firstly in the as-prepared
sample and can decay into the low TC phase by exposing to ambient atmosphere
for certain duration. Especially the high TC phase can reappear from the
decayed sample with the low TC phase by vacuum annealing. It is also found that
the CDW/SDW order occurs only with the 6 K superconducting phase. These notable
features and alteration of superconductivity due to the post-processing and
external pressure can be explained by the scenario of electronic
phase-separation.
