Spin fluctuations are reported near the magnetic field driven quantum critical point in YbRh2Si2. On cooling, ferromagnetic fluctuations evolve into incommensurate correlations located at q0=+/- (delta,delta) with delta=0.14 +/- 0.04 r.l.u. At low temperatures, an in plane magnetic field induces a sharp intra doublet resonant excitation at an energy E0=g muB mu0 H with g=3.8 +/- 0.2. The intensity is localized at the zone center indicating precession of spin density extending xi=6 +/- 2 A beyond the 4f site.
@article{arxiv.1207.4411,
title = {From incommensurate correlations to mesoscopic spin resonance in YbRh2Si2},
author = {C. Stock and C. Broholm and F. Demmel and J. Van Duijn and J. W. Taylor and H. J. Kang and R. Hu and C. Petrovic},
journal= {arXiv preprint arXiv:1207.4411},
year = {2015}
}
Comments
(main text - 4 pages, 4 figures; supplementary information - 3 pages, 3 figures; to be published in Physical Review Letters)