Weak localization and fluctuation electron-electron interaction in disordered indium films

The effects of perpendicular magnetic fieldsH on the temperature dependence of the resistanceR(T) (T<20 K), the superconducting transition temperatureT _c and the fluctuation superconductivity (T«T _c ) have been investigated on high-resistance (R _>1 kOhm) indium films prepared by simultaneous condensation of the metal and hydrogen onto a substrate cooled to 5 K. AtT«T _c the resistance slightly decreased with rising temperature, in agreement with the weak localization and electron-electron interaction (EEI) theories. Processing of theR(T, H) curves in terms of the theories permitted the electron phase relaxation time (T) to be determined and the time _so of electron spin relaxation due to spin-orbital interaction (SOI) to be estimated. In the temperature rangeT–T _c /k the effect of the fluctuation EEI on conductivity was investigated. The contribution of the fluctuation EEI is shown to be given by a sum of two corrections: the Cooper and the Maki-Thompson ones. In the rangeT–T _c /k the influence of magnetic field was investigated on the transition from two-to zerodimensional fluctuations of the order parameter resulting from temperature increase in the rangeT>T _c . Increasing field was found to cause enlargement of the zero-dimensional fluctuation critical region and lowering of the fluctuation dimensionality alteration temperature, leading eventually to complete two-dimensional fluctuation suppression. The experimental dependencesT _c (H) experienced, in addition to orbital effects of the magnetic field, depairing effect of the field on electron spins. Thus the _so magnitude could also be estimated and proved roughly equal to _so determined from the analysis ofR(T, H)