Magnetoresistance in Granular Metal–Dielectric Composites

Resumo

Magnetoresistance in granular composites over a broad concentration range (25 < x < 60%) was investigated. In the studied composites both-positive and negative magnetoresistance were observed. Positive magnetoresistance at x ≤ 45 reaches 20% in magnetic fields of 11–12 kOe. This result can be explained by assuming that in the analyzed composites clusters and granules of isolated magnetic particles co-exist. This is why, they are characterized by different values of magnetic anisotropy and the presence of a dipole-dipole interaction between the clusters and the nearest-neighbor particles.