Low temperature magnetoresistance measurements on bismuth nanowire arrays

We present low temperature resistance R(T) and magnetoresistance measurements for Bi nanowires with diameters between 100 and 500 nm, which are close to being single-crystalline. The nanowires were fabricated by electrochemical deposition in pores of polycarbonate membranes. R(T) varies as T 2 in the low temperature range 1.5 K < T < 10 K and exhibits a maximum which shifts from 140 to 250 K with decreasing wire diameter. An unexpected effect is observed in R(T) when a magnetic field is present. It can be related to the temperature dependence of the magnetoresistance. The transverse magnetoresistance of all samples shows a clear B1.5 variation. Its size depends strongly on the diameter of the wires but only weakly on temperature. Finally, a steplike increase in the magnetoresistance of our sample with a wire diameter of 100 nm was found and this might be attributed to a transition from one-dimensional to three-dimensional localization.