Electrical nonlinearity of magnetodynamic nature in metals at high levels of energy dissipation

Abstract

In cryoconductors of Corbino geometry made from uncompensated metals the phenomenon of nonlinear coupling between the electrical field and the current density is observed at rather low density of a radial current. Nonlinearity is caused by a-magnetic field of azimuthal drift of carriers through the Lorentz force in ал external magnetic field of the solenoid. In this report the results of investigation of the nonlinear phenomena in aluminum disks at different levels of dissipation of an electrical energy are presented. The level of dissipation substantially redefines the thermal condition of system. The reason of the last is inefficiency of a heat-removal power at levels adequate to a boiling crisis of liquid refrigerating medium helium. Research was carried out by a method of registration of current-voltage characteristics in a current mode. Samples had different surface-volume ratios at a variation of their geometrical forms. In particular the samples in the form of a disk with a constant height along radius and also with a hyperbolic axial section are applied. Measurements carried out in magnetic fields up to 8 T at loading current density up to 800 A/cm^2. The opportunity of existence of the asymptotic steady temperature-electric domain structure is experimentally proved. Domains result in stabilization of current-voltage characteristic through the mechanism of non -local heat removal in-conditions of negative differential conductivity. The role of magnetic gradient in obtaining stabilization state is analyzed at various orientations of a vector of carrier drift velocity adequate collinear or anti-collinear geometry of charge flux.