From incommensurate correlations to mesoscopic spin resonance in YbRh2Si2

Collin Broholm

Institute for Quantum Matter and Department of Physics and Astronomy,

Johns Hopkins University, Baltimore, Maryland USA 21218

NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, Maryland 20899


    Spin fluctuations are reported near the magnetic field driven quantum critical point in YbRh2Si2 [1]. On cooling, ferromagnetic fluctuations evolve into incommensurate correlations with a characteristic in-plane wave vector of qm = (δ,δ) with δ=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 gμBμ0H with g=3.8±0.2. The intensity is localized at the zone center and has a width in momentum space indicating precession of spin density extending ξ = 6 ± 2 Å beyond the 4f site.


[1] C. Stock, C. Broholm, F. Demmel, J. Van Duijn, J. W. Taylor, H.J. Kang, R. Hu, and C. Petrovic, Phys. Rev. Lett. 109, 127201 (2012).

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