A non-Griffiths-like clustered phase above the Curie temperature of the doped perovskite cobaltite La$_{1-x}$Sr$_{x}$CoO$_{3}$*

The existence of preformed clusters above the \textit{Tc} of the doped perovskite manganites is well established and, in many cases, conforms to the expectations for a Griffiths phase. We show here that the phase-separated perovskite cobaltite (La$_{1-x}$Sr$_{x}$CoO$_{3})$ also exhibits a clustered state above the \textit{Tc} in the ferromagnetic phase. The formation of magnetic clusters at a well-defined temperature ($T$*) is revealed in the small-angle neutron scattering, d.c. susceptibility, and resistivity. Remarkably, this clustered state has none of the characteristics of a Griffiths phase; the deviation from Curie-Weiss behavior is opposite to expectations and is not field dependent, and $T$* does not correspond to the undiluted \textit{Tc}. These results demonstrate that although the Griffiths phase may occur in many systems with quenched disorder, it is not universally applicable to the randomly doped transition metal oxides.