Magnetotransport and thermopower of single Bi_0.92Sb_0.08 nanowires

Abstract

This Letter reports on temperature‐dependent electrical measurements of single Bi0.92Sb0.08 nanowires with diameters between 220 nm and 350 nm. The magnetoresistance effect under transverse magnetic fields of ±2 T and the Seebeck coefficient S are measured in the temperature range of 50–300 K. Additionally, the influence of an annealing step on the transport properties is investigated. The as‐prepared wires show heterogeneous temperature dependent behavior, whereas the annealed wires show semiconductive behavior. The room temperature value of the resistivity of the wires is between 2 × 10–6 Ωm and 1.4 × 10–5 Ωm. Magnetoresistance effects up to 15% at 50 K for the as‐prepared nanowires and up to 23% for the annealed wires are observed. The temperature dependent Seebeck coefficient of single wires is determined. The as‐prepared wires show a rise of the absolute value of S with temperature and it seems to saturate at room temperature. In contrast to this, the annealed wires show a linear increase of S. The room temperature values of S are –55 µV K–1 and –45 µV K–1, respectively. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Magneto-resistive property study of direct and indirect band gap thermoelectric Bi-Sb alloys

“…3,[20][21][22] But there is a lack of systematic investigation on magneto-transport properties of semiconducting Bi-Sb alloy, which is a remarkable n-type TE material. [23][24][25][26] However, the general consensus regarding origin of giant and Linear MR (LMR) observed in these TE alloys is yet to be obtained. Also, the relation between the MR and carrier mobility has still not been revealed for Bi-Sb alloys.…”

“…29 Earlier similar behavior has been observed in single crystal Bi thin films 8 , single crystals of Bi 2 Se 3 and Bi 2 T e 3 , 7,14 Bi 0.92 Sb 0.08 nanowire. 26 But, the non saturating MR observed at high magnetic fields should originate from another mechanism, the origin of which is quite contradictory. 5,7,14 The square root of the prefactor of the quadratic term (A 0 ) 1 2 , extracted from fitting low field MR data [Figure 2 (inset)], is plotted in Figure 3 for both Bi 1−x Sb x (x = 0.10, 0.14) samples.…”

“…Similar temperature dependence of µ for single-crystal Bi and Bi-Sb nanowire was also reported and the present estimated dependences are in good agreement with this trend. 26,31 As µ is suppressed by scattering at grain boundaries, its magnitude in polycrystalline Bi-Sb alloy will be always lower than that of Bi single crystal. 11 Further, with increasing Sb concentration number of scattering sites increases, this tends to decrease µ in higher Sb content sample e.g., Bi 0.86 Sb 0.14 .…”

Electrochemical synthesis of highly ordered nanowires with a rectangular cross section using an in-plane nanochannel array

“…Unless all synthesis steps can be successively conducted without a vacuum break, the sample is exposed to ambient air, humidity or process chemicals which can lead to unwanted oxidation or etching of the nanowires. In the case of bismuth nanowires for example, a strong surface oxide layer is formed upon release from the template which needs to be removed before an ohmic contact between the deposited contact pads and the wire becomes possible [29,30]. In summary, all these steps until its final incorporation into a measurement device pose a significant challenge.…”

Magnon contribution to the magnetoresistance of iron nanowires deposited using pulsed electrodeposition

“…In summary we have measured the magnon stiffness of electrodeposited iron nanowires using a versatile synthesis technique. This technique can of course be adapted for any other kind of nanowire that can be deposited using electrodeposition, for example Bismuth wires which are known to create a very strong surface oxide [23].…”