Spin ordering and coherent atomic motion in bcc solid 3He

We propose a new model to describe the nuclear magnetism of bcc He-3. According to this model, in bcc He-3 there is correlated zero-point motion of the nuclei, which gives rise to electric and magnetic polarizations of the electronic cloud. Our model describes the resulting modification of the phonon spectra and predicts new localized modes, which have been observed during the past year. The polarization of the electronic cloud leads to hyperfine magnetic interactions with the nuclear spin. Magnetic ordering results from an indirect spin-spin interaction. The model predicts correctly both the u2d2 symmetry of the ordered phase and the volume dependence of the magnetic interaction. We further predict the excitation branches (spin waves) of the ordered phase. (C) 2003 Elsevier Science B.V. All rights reserved.