On Hall voltage and change of conductivity in transverse magnetic fields of pressed PbO2 powder

The electrical conductivity of a conducting powder is influenced by the properties of the grain surface as well as the grain core. By appropriate variation of pressure and electric frequency, the two contributions can be separated, as long as the grains have shapes nearly like spheres. From experimental data on pressed powders one can thus obtain information concerning carrier density and mobility of bulk material. Results for PbO₂ obtained in this way agree well with the properties of bulk PbO₂ samples reported in the literature.