Resistivity of Iron as a Function of Temperature and Magnetization

The temperature dependence of the resistance of iron has been measured in the range 1 to 4.2°K. Single-crystal iron specimens 100 to 300 μ in diameter with residual resistance ratios up to 2100 were used in the experiments. The dominant temperature dependence in this range is linear with average coefficients of 8.2×${10}^{-4\mathrm{}}$ and $2.14\times {10}^{-4\mathrm{}}{\mu }_A$ cm/°K in the flux-closed and -saturated states, respectively. These coefficients are an order of magnitude larger than those observed by previous experimenters. Careful control of the magnetic state of the crystal seems to remove most of the $T^2$ dependence in this temperature range. The results are discussed in terms of the general electron-magnon scattering theories developed by Turov. Deviations from Ohm's law and large negative magnetoresistance effects are observed, and these are taken into account in making the measurements. Preliminary measurements have also been made in the range 77 to 294°K, and results are in general agreement with previous measurements by White and Woods.