Anisotropic thermoelectrics based on an extruded sample of Bi0.85Sb0.15 solid solution doped with tellurium

The effects of tellurium impurities and heat treatment on the anisotropy of the electrical and thermal properties of extruded samples of the Bi0.85Sb0.15 solid solution in the range of ~77 300K and magnetic field strengths H up to ~74x104 A/m are studied. It was found that in extruded samples doped with tellurium and subjected to heat treatment, electrons scatter more strongly in the perpendicular direction of extrusion than in the direction of the extrusion axis, and during annealing, the increase in mobility, electrical conductivity and thermal conductivity in the direction parallel to the extrusion axis is greater than in the perpendicular direction. Therefore, in samples that have undergone annealing, the anisotropy s at ~77 K is opposite to that of samples that have not undergone annealing. In annealed samples of Bi0.85Sb0.15 with 0.001 at.% tellurium, the absolute values ​​of α in the perpendicular direction of the extrusion axis are more sensitive to the magnetic field than in the parallel direction, and the anisotropy of the thermoelectric power (Dα) at ​​a magnetic field strength of H=42x104A/m reaches the value Dα=80 kV/K at ~77K.