Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 53: Correlated Electrons: Heavy Fermions
TT 53.12: Vortrag
Donnerstag, 14. März 2013, 12:30–12:45, H19
Magnetic field dependence of multiple order parameters in CeB6 — •G. Friemel1, H. Jang1, A. Schneidewind2, Y. Li1, A. V. Dukhhenko3, N. Y. Shitsevalova3, N. E. Sluchanko4, A. Ivanov5, V. B. Filipov3, B. Keimer1, and D. S. Inosov1 — 1MPI für Festkörperforschung, Stuttgart, Germany — 2FRM-II, Garching, Germany — 3Institute for Problems of Material Sciences, Kiev, Ukraine — 4General Physics Institute, Moscow, Russia — 5Institut Laue-Langevin, Grenoble, France
The heavy fermion (HF) antiferromagnet CeB6 is known for exhibiting an antiferroquadrupolar (AFQ) order below TQ=3.2 K at Q=R(1/2,1/2,1/2), which was confirmed by resonant x-Ray and polarized neutron diffraction. Furthermore, the compound orders antiferromagnetically (AFM) in a double-k pattern below TN=2.3 K, which was so far neglected in the discussion of this compound. Only recently we could observe a spin exciton mode formation in the AFM state at ℏω=0.5 meV by inelastic neutron scattering, which can be understood as a feedback effect of the AFM order on the itinerant spin dynamics. By applying magnetic field the AFM order becomes quickly suppressed at Bc=1 T, whereas the intensity at R(1/2,1/2,1/2) stays constant up to BQ=1.7 T, suggesting that it belongs to an unknown phase different from AFM and AFQ, with the latter setting in at B>BQ. The exciton mode energy surprisingly becomes enhanced in field, parallel to the emergence of multiple other modes reaching into the AFQ state. These latter modes show a strong field dependence in energy, but are absent in the zero field AFQ phase above TN.