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

The frequency-response complete permeability of polycrystalline perovskite La0.7Sr0.3MnO3 with mean grain size range from 1200 to 45 nm has been inves tigated. The pronounced dispersions with relaxation character have been obs erved in the samples with mean grain size larger than 105 nm. The dispersio ns 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 relaxa tion frequency. (C) 2001 Elsevier Science B.V. All rights reserved.