Ohm's law violation in spin glasses

Abstract

Electrical resistivity rho s of metal containing ordered (spin glass) magnetic impurities is calculated. Two limiting cases are considered: (i) tau e/ tau i<<1 ( tau e and tau i are the times of collisions of electrons with each other and with nonmagnetic impurities); (ii) square root ( tau i/ tau ph)<<1 ( tau ph is the electron-phonon collision time). In both cases at solution of the kinetic equation it was assumed that at the first stage magnetic impurities do not take part in the conduction electron relaxation. It is shown that dependence of rho s on electric field (or on current density) is strongly nonlinear irrespective of the relaxation regime, and derivatives of rho s with respect to field or current contain a characteristic cusp which can be easily recorded experimentally. The calculated effect can be observed at relatively small current densities j approximately 105-106 A cm-2.