The enhancement effect in the domain and domain wall in Fe⁵⁷ nuclear magnetic resonance

We observed both the nuclear magnetic resonance (NMR) signals from the domain and the domain wall in pure iron particles. In the multi-domain state, the total signal was divided into the signal from the domain and that from the domain wall and the enhancement factors were evaluated separately. The average enhancement factors in the domain walls and the domains were estimated to be about 136 and 34, respectively, in zero field, and remained constant in external dc field in the multi-domain state. In the single domain state, it was observed that the enhancement factor is inversely proportional to external field, and the resonance frequency decreases linearly with external field. From the comparative study between the magnetization curve and the variation curves of the domain wall signal and the resonance frequency with external field, we showed that NMR could give useful information on the magnetization process.