Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 5: f-Electron Systems and Heavy Fermions I
TT 5.2: Vortrag
Montag, 12. März 2018, 09:45–10:00, H 3005
Magnetic field dependence of the zone-center excitation in the heavy-fermion metal CeB6 — •P. Y. Portnichenko1, S. E. Nikitin1,2, S. V. Demishev3, A. V. Semeno3, H. Ohta4, A. V. Dukhnenko5, N. Yu. Shitsevalova5, V. B. Filipov5, Z. Huesges6, Z. Lu6, A. Schneidewind7, and D. S. Inosov1 — 1TU Dresden, Germany — 2MPI-CPfS Dresden, Germany — 3GPI of RAS, Moscow, Russia — 4Kobe University, Japan — 5IMPS, Kiev, Ukraine — 6HZB, Berlin, Germany — 7JCNS, Jülich, Germany
The heavy-fermion metal CeB6 with a simple cubic crystal structure is characterized by a rich magnetic-field – temperature phase diagram. Neutron scattering experiments showed an intense ferromagnetic collective mode that dominates the magnetic excitation spectrum. ESR measurements revealed a significant anisotropy of the g-factor as a function of the applied field direction. The g-factor remains temperature independent and isotropic for field directions like [110] or [111], but shows a noticeable anomaly for B ∥ [100]. Knowing that the energy of the ESR resonance matches perfectly with that of the field-induced INS excitation, we expected a corresponding softening of the zone-center mode in field parallel to [100]. However, our results show absolutely no temperature effect on the g-factor at high fields. We observe significant difference of the resonance energy upon change of the field direction. Observed difference of the resonance energy can be explained either by anisotropy or by redistribution of the spectral weight between two collective magnetic modes, which we perceive as a change of the resonance energy.