Plastic-deformation-induced low-temperature anomalies of the resistivity of polycrystalline copper and aluminum

Abstract

The temperature dependence of the electrical resistivity ρ of pure polycrystalline aluminum and copper after plastic deformation is investigated in the temperature interval 4.2–300 K. Using heat treatment as a tool for changing the crystallite size d and structural perfection of the sample, it is determined how ρ depends on the ratio of d to the electron mean free path le and on the degree of deformation of the Cu and Al. At temperatures below 10 K the ρ(T) curves of the deformed samples of polycrystalline copper and aluminum exhibit minima and maxima. At higher temperatures a more complicated dependence of ρ(d/le) is observed. It is found that in the region of the anomalous skin effect the experimentally determined and theoretically calculated values of the surface resistance Rs agree only in the case when the electron mean free path is smaller than the size of the crystallites.

Oscillations of kinks on dislocation lines in crystals and low-temperature transport anomalies as a “passport” of newly-induced defects

“…Experimental investigations for many years [1][2][3][4] and more recent works [5][6][7][8][9] have led to revealing features in a behavior of kinetic coefficients in perfect metallic samples after introducing into them a small number of dislocations (10 7 -10 8 cm À2 ) at weak plastic deformation. A significant deviation of the temperature dependence of thermal conductivity from a linear law in samples at helium temperature has indicated the manifestation of inelastic electron scattering by soft-mode vibrations which has been suppressed by subsequent sample annealing or by increasing the density of introduced dislocations by an order of magnitude up to (10 9 cm À2 ) and more.…”