Thermal Conductivities of Bismuth Single Crystals as Influenced by a Magnetic Field

Abstract

The thermal and electrical conductivities of two specimens of Bi single crystals were determined as a function of temperature and orientation of magnetic field relative to their crystallographic axes. These effects were observed at temperatures ranging from -170\ifmmode^\circ\else\textdegree\fi{}C to -50\ifmmode^\circ\else\textdegree\fi{}C. The first specimen was mounted with its trigonal axis $P\ensuremath{\perp}$ to $H$ and \ensuremath{\parallel} to heat or current flow. The second specimen was mounted with $P\ensuremath{\perp}$ to heat or current flow and $P\ensuremath{\perp}$ or \ensuremath{\parallel} to $H$. In this specimen it was also known that the heat or current flow was \ensuremath{\perp} to the traces in the (111) plane formed by the intersection of the (111) and the ($11\overline{1}$) planes. A magnetic field of 7800 gauss was used and the crystallographic orientation was determined by means of variations in electrical resistance as the field was rotated about the specimen. For the first specimen, $P\ensuremath{\parallel}$ to heat and current flow, the decrease in thermal and electrical conductivity with the field perpendicular to any one of the binary axes was greater than when the field was parallel to any one of them. For the second specimen, $P\ensuremath{\perp}$ to heat and current flow, the decrease in thermal conductivity with $H\ensuremath{\perp}P$ was greater than the corresponding decrease with $H\ensuremath{\parallel}P$, whereas the decrease in electrical conductivity for these two positions were less and greater, respectively.