Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 54: Correlated Electrons: Heavy Fermions
TT 54.2: Vortrag
Mittwoch, 2. April 2014, 09:45–10:00, HSZ 204
Intense ferromagnetic fluctuations in the heavy-fermion antiferromagnet CeB6 — •D. Inosov1,2, H. Jang2, G. Friemel2, J. Ollivier4, A. V. Dukhnenko3, N. Yu. Shitsevalova3, V. B. Filipov3, and B. Keimer2 — 1Inst. für Festkörperphysik, TU Dresden, Germany. — 2MPI für Festkörperforschung, Stuttgart, Germany. — 3Inst. for Problems of Material Sciences, Kiev, Ukraine. — 4Inst. Laue-Langevin, Grenoble, France.
Heavy-fermion metals exhibit a plethora of low-temperature ordering phenomena, among them the so-called hidden-order phases that in contrast to conventional magnetic order are invisible to standard neutron diffraction. One of the oldest and structurally simplest hidden-order compounds, CeB6, is famous for an elusive phase attributed to the antiferroquadrupolar ordering of Ce 4f moments. In its ground state, CeB6 also develops a more usual antiferromagnetic (AFM) order. Hence, its essential low-temperature physics was always considered to be governed by AFM interactions between the dipolar and multipolar Ce moments. Our recent inelastic neutron scattering experiments overturned this established perspective by uncovering an intense ferromagnetic (FM) low-energy collective mode that dominates the magnetic excitation spectrum of CeB6, thus placing CeB6 much closer to a FM instability than could be anticipated. This propensity of CeB6 to ferromagnetism may account for much of its unexplained behavior, such as the existence of a pronounced electron spin resonance, and should lead to a substantial revision of existing theories that have so far largely neglected the role of FM interactions.