Electrical Resistivity Studies of Iron–Nitrogen Solid Solutions

The electrical resistivity of iron–nitrogen solid solutions prepared from high purity iron has been studied as a function of applied longitudinal magnetic fields up to 60 kOe at 4.2°K. It is demonstrated that the presence of interstitial nitrogen increases the resistivity of iron and alters the shape of resistivity vs. magnetic field curves, particularly at low fields. By extrapolating the data to B = 0, where B is the internal magnetic induction, it has been possible to determine that the residual resistivity contribution per 1 at% nitrogen in solid solution in iron is about 0.1 μΩcm. At 78°K the value is approximately 7.0 μΩcm. Such a large positive deviation from the Matthiessen rule is characteristic for iron alloys with another transition metal as a solute. Magnetoresistivity data of iron‐nitrogen solid solutions (but not pure iron) very approximately obey the Kohler rule.