Magnetoresistance of a ferromagnetic metal nanocomposite with nonsphericalgranules

It is experimentally established that the magnetoresistance of a Fe-x(SiO2) (1-x) nanocomposite (x = 0.6) in a strong magnetic field is described by a logarithmic function of the field strength. This field dependence is incons istent with the well-known theory of the giant magnetoresistance in ferroma gnetic nanocomposites. A model is developed according to which the unusual behavior of the magnetoresistance is explained by nonsphericity of the mate rial grains, exhibiting a broad variety of shapes. The experimental results agree with conclusions and predictions of the proposed model. (C) 2001 MAI K "Nauka/Interperiodica".