An Analysis Method of Antiferromagnetic Powder Patterns in Spin-Echo NMR under External Fields

An analysis method of antiferromagnetic powder patterns in spin-echo NMR under external fields is shown. Spin-echo spectra for powdered antiferromagnets under external fields have been calculated in both the field- and frequency-sweeping cases on the assumption of the random distribution of the direction of antiferromagnetic internal fields. In this calculation, the effect of the non-perpendicularity between the axis of the sample coil and the resonance field is taken into account. From the comparison with the observed spectra which have been measured for proton in the antiferromagnetic CsMnCl 3 ·2H 2 O in the powdered state, the present analysis method is shown to be applicable to the analysis of the spectra of real antiferromagnetic materials.