Itinerant electron behaviour and long-range ordering in La_1-xSr_xCoO₃

Abstract

Electrical resistivity of La_1-xSr_xCoO₃ is reduced significantly by the substitution of Ni³⁺ ions in place of the cobalt ions. In the La_1-xSr_xCo_1-yNi_yO₃system, for small values of x(x=0.05) superparamagnetic clusters seem to be formed at lower temperatures (<300 K). The formation of such clusters is not affected by the presence of nickel ions. When x is large, the occurrence of long-range ordering seems to depend on the itinerancy of charge carriers.