Resistance Minimum of Magnesium: Electrical and Thermal Resistivities

The thermal and electrical resistivities of two specimens of magnesium have been measured in the temperature range 1.5 to 25°K. One specimen was a spectrographically pure rod of 99.98+% magnesium with 0.013% iron as the major contamination. The second specimen was 99.95+% pure with 0.043% manganese as the only significant contaminant. The electrical resistivity of the purer material passed through a minimum at ∼5°K and increased by 1.7% as the temperature was lowered to 1.5°K. In the same specimen, the thermal resistivity at the lowest temperature exhibited a positive deviation from normal behavior (defined by $w=\alpha T^2+\frac{\beta }{T}$) of the same order of magnitude. Between 5° and 15°K a negative deviation was observed in the thermal resistivity.