Abstract
The NMR properties of Mn in the Dzialoshinsky-Moriya antiferromagnet McCO3 are reported. The crystal was investigated between 20.4 and 1.4°K and in fields from zero to 20 kG. Large frequency pulling of the ferromagnetic NMR mode was observed in good quantitative agreement with theory. The unpulled frequency extrapolated to zero absolute temperature was 639.1 Mc/sec. Deviations of the unpulled frequency as a function of temperature are attributed to a temperature dependence of the canting angle. Inhomogeneous broadening due to a spread in the anisotropy field is described. Enhancement of the rf power and the effect of saturation on the position and shape of the resonance line are discussed. Some properties of an additional line observed at frequencies above the main resonance line are also described.