Hall Effect in CoO, NiO, and α-Fe 2 O 3

摘要: The Hall coefficient ${R}_{H}$ and resistivity $\ensuremath{\rho}$ have been measured on ceramic samples of $p$-type CoO NiO between 200 1500\ifmmode^\circ\else\textdegree\fi{}K $n$-type $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ 960 1500\ifmmode^\circ\else\textdegree\fi{}K. Results obtained single-crystal are also reported. Seebeck-effect data considered in the discussion results. For paramagnetic phase $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$, behavior deviates drastically from that found case a normal-band semiconductor. sign is opposite to normally expected. corresponding Seebeck effect has normal sign. remains inversely proportional charge-carrier concentration. Furthermore, mobility (${\ensuremath{\mu}}_{H}=\frac{|{R}_{H}|}{\ensuremath{\rho}}$) value which smaller than for drift (${\ensuremath{\mu}}_{D}$). difference amounts two orders magnitude about factor 4 $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$. Below N\'eel temperature, anomalous cases thought be due an interaction charge carriers magnetization induced material by applied magnetic field. In does not seem influenced appreciably transition at temperature. ${\ensuremath{\mu}}_{H}$ high temperatures lower ${\ensuremath{\mu}}_{D}$. A Hall-effect with regard mechanism electrical conduction materials under consideration presented.