The use of nuclear spin-echoes to measure hyperfine field distributions in ferromagnets

A general expression for the nuclear magnetic resonance spin-echo signal in a ferromagnet is derived. Spin echoes stimulated from hyperfine field distributions in Co alloys are interpreted in terms of the analysis, and the observed behaviour of spin-echo shape as a function of excitation conditions is shown to be consistent with the predictions. The theoretical expression is used to obtain the conditions under which measurement of the spin-echo amplitude as a function of excitation frequency can be expected to reflect the hyperfine field distribution in a ferromagnet.