Nuclear magnetic resonance of fe⁵⁷ in unenriched fe

The nuclear magnetic resonance of Fe57 has been observed in iron specimens in the form of powders of various sizes, foils, and whiskers. Our results are consistent with previously reported work of Gossard, Portis, and Sandle on enriched iron, and with the work of Robert and Winter on natural iron. We find that the resonant frequency varies slightly among nominally pure iron specimens taken from different sources, suggesting that it is somewhat sensitive to impurity content. Prestrain of the specimen has a marked effect, the resonance in cold-rolled foil being very broad and weak compared to that observed in annealed foils. Observations of nuclear magnetic resonance in iron whiskers oriented both axially and transversely in the rf coil offer interesting confimation of the domain wall enhancement mechanism put forth by Gossard and Portis. The temperature dependence of the Fe57 resonance has been investigated in the range 77°-785°K. © 1961 The American Institute of Physics.