NMR in Magnetically Ordered Solid 3He

Magnetically ordered solid ³He, produced by compressional cooling to T~1 mK, has been studied by high-resolution NMR at fields up to 2.98 T. In the ordered solid, at low fields B₀<=410, mT, peaks in the spectrum above and below γB₀2π characteristic of antiferromagnetic ordering, are observed. For B₀>=430 mT, there is a temperature-dependent shift of the resonance to higher frequencies and a large rapid growth in magnetization, beginning at the ordering temperature.