Grain-size dependence of complex permeability in polycrystalline perovskite La0.7Sr0.3MnO3

Abstract The frequency-response complex permeability of polycrystalline perovskite La 0.7 Sr 0.3 MnO 3 with mean grain size range from 1200 to 45 nm has been investigated. The pronounced dispersions with relaxation character have been observed in the samples with mean grain size larger than 105 nm. The dispersions are due to domain wall displacements. The damping of wall displacements mainly originates from the eddy currents associated with wall motions. The resistivity and mean grain size may be responsible for the change of relaxation frequency.