EXTRAORDINARY HALL-EFFECT (EHE) OF FERROMAGNETIC COMPOSITES IN THE EFFECTIVE-MEDIUM APPROXIMATION

The expression for the EHE coefficient R(s) of ferromagnetic composite s is derived in the framework of the effective medium approximation. I n the case of a composite ferromagnetic metal-dielectric, R(s) increas es monotonically as the concentration of the magnetic component c decr eases and in the dielectric region (c less than or equal to 1/3) R(s) = 9R(s1)(1 - c), where R(s1) is the EHE coefficient of the ferromagnet ic component. The dependences of R(s) on composition are calculated fo r composites ferromagnetic-paramagnetic metals, ferromagnet-ferromagne t. The typical relation R(s) similar to rho 2 for uniform ferromagnets , where rho is electroresistivity, is not fulfilled in all the cases c onsidered.