A -site dependent percolative thermopower and Griffiths phase in Pr <inf>(0.7-x)</inf>Ho <inf>x</inf>Sr <inf>0.3</inf>MnO <inf>3</inf> (x=0.0, 0.04, 0.08, and 0.1)

We report our analysis of thermopower S (T) of Pr(0.7-x) Hox Sr0.3 Mn O3 (x=0, 0.04, 0.08, and 0.1) compounds within a percolative framework and correlate the results with the existence of a Griffiths phase. The Griffiths temperature, at which ferromagnetic metallic clusters nucleate above TC, is evaluated. We further show that the Griffiths phase extends over a higher temperature range above TC with increase in the variance of ionic radii of the A site. © 2005 American Institute of Physics.