Magnetization reversal in granular powder systems

Abstract In this paper, the magnetization reversal in substituted BaFe 12−2 x Co x Ti x O 19 nanoparticles is examined. Measurements of fluctuation field ( H f ) have shown that the behavior of H f is greatly influenced by the substitution level ( x ). At x =0.71, H f is observed to be slowly varying with field, which is expected for a particulate system when both distributions (anisotropy fields and particle volumes) have comparable standard deviations. Hence a constant behavior of H f with field cannot be used as an indication of single activation energy in the system.