The Critical Dynamics of Hot Electrons in a Ferromagnetic Semiconductor at T = T_c

Abstract

The high-field transport in ferromagnetic semiconductors has been theoretically investigated in many papers /l/. It is clear now that both above and below the Curie temperature Tc, there should occur a strong electric field dependence of the non-equilibrium conductivity d . In the vicinity of Tc this quantity has been analyzed in /2, 3/ where, for the case of a zero magnetic field 6, the dependences of d on electric field E and IT -Tcl were obtained.In this paper we shall consider the critical behaviour of the hot electron conductivity for a ferromagnetic semiconductor in constant magnetic and strong electric fields. We assume that + a) the unit lattice cell is a simple cubic one, b) the localized magnetic moments may be described within the framework of the isotropic Heisenberg model, c ) the conduction electrons a r e non-degenerate (broad conduction band limit) and interact with localized spins via the s-d exchange interaction.