Enhancement of thermoelectric figure of merit of BI1-ХSBХ thin wires under elastic stretch in a magnetic field

Abstract

This paper studied a combined effect of a longitudinal magnetic field and elastic stretch on thermoelectric properties of Bi0.88Sb0.12, thin wires obtained by the Ulitovski method and doped with donor and acceptor impurities. Measurements were performed in the temperature range of 4.2 - 300 K, in magnetic fields up to 14 Т. Maximum value of relative elongation under elastic stretch made up 1.3% at Т = 4.2 - 200 K. Diameter of samples varied from 200 nm to 5 µm and was controlled on a SEM. It was established that at temperature 120 K in a magnetic field up to 0.4 Т a growth in thermopower by 14-20% is observed. By means of elastic stretch, drastic resistance growth in the region of magnetic fields 0.4 Т typical of the bulk bismuth samples and non-deformed wires could be suppressed. This brought about considerable power factor increase in the region of temperatures beyond 120 K.