Structural Defects and Electrical Properties of Extruded Samples of Bi_{85}Sb_{15} Solid Solutions

Authors: Farkhad SAMEDOV, Mail TAGIEV

Abstract: The effect of 5 hours annealing in vacuum $\sim 10^{-3} Pa$ at $503 K$ on the electroconductivity $(\sigma)$, the coefficient of thermoelectric power $(\alpha)$ and the Hall coefficient $(R_x)$ for extruded samples of $Bi_{85}Sb_{15}$ has been investigated in the temperature range from $\sim 77 K$ up to $\sim 300 K$. The samples were taken with a different concentration of $Pb$ (lead) up to $\sim 0.1 a.w \%$. The anisotropy of electrical properties of these samples was also studied in the temperature range between $77 K$ and $300 K$ and in the presence of magnetic field up to $\sim 74 \times 10^4 A/m$. It is established that unannealed samples are nearly insensitive to the amount of lead and to the strength of the applied magnetic field. With increasing the amount of $Pb$ we observed inversion of signs of $\alpha$ and $R_x$ from $n$ to $p$-type. The obtained results are interpreted within the assumption that the extrusion of $Bi_{85} Sb_{15}$ samples may give rise to a creation of deformation defects which act as scattering centers for electrons and disappear with annealing.

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