Influence of metal-metalloid elements on the electrical resistance of amorphous materials

We report systematic studies on the electrical resistivity, ρ, in the amorphous transition metal based alloy series T1−yGy, with T = A1−xBx (where A,B = Fe, Co, Ni, Cr, Mn) and the metalloid G (=P, B, Si, Al) over the temperature range 20 mK to 300 K. All the alloys studied show a minimum in the resistivity at a characteristic temperature Tmin which varies from 8 K to 250 K depending on the system. For a given system the resistivity rise below tmin is found to be a maximum around the critical conc region where the magnetic long-range order parameter →0. Also, in all the alloys below the resistance minimum it is found that dρ (T)/dT∼–ρ (T) with deviations setting in at lower temperatures. The coefficient of the T2 term in ρ above Tmin is strongly influenced by the metalloid concentration.