  The compound, Ca3CoRhO6, containing magnetic Co-Rh chains intervened by Ca
ions, has been known to be one of the few exhibiting partially disordered
antiferromagnetic structure (PDA) due to geometrical frustration. Here, we
report the influence of partial replacement of Ca by Y on the magnetic
anomalies by investigating the solid solution, Ca(3-x)Y(x)CoRhO6 by bulk
measurements. There are profound changes in the magnetic behavior, the most
notable one being that the features attributable to spin-chain magnetism and
PDA structure get suppressed dramatically by a small replacement of Ca by Y (x=
0.15), despite the fact that the magnetic chain is not disrupted. This finding
suggests that this compound is on the verge of PDA-structural-instability.
