Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.15: Poster

Thursday, March 17, 2011, 10:00–13:00, P1

Magnetic excitations in YbCo₂Si₂ — •O. Stockert¹, A. Haase¹, K. Schmalzl², C. Krellner¹, N. Mufti¹, and C. Geibel¹ — ¹Max-Planck-Institut CPfS, Dresden, Germany — ²Forschungszentrum Jülich, Jülich Centre for Neutron Science at Institut Laue-Langevin, Grenoble, France

Quantum phase transitions and their origin are still open issues of current research in condensed matter physics. Although YbRh₂Si₂ is a model system to study quantum criticality, microscopic studies by neutron scattering are prevented because of the large absorption of Rh for neutrons, the small ordered moment and the small available samples. Instead, we investigated YbCo₂Si₂ being isoelectronic and isostructural to YbRh₂Si₂. YbCo₂Si₂ orders antiferromagnetically below T_N ≈ 1.7 K in an incommensurate structure and changes to a commensurate structure below T_L ≈ 0.9 K. Using inelastic neutron scattering we studied in detail the spin excitations in the low temperature commensurate phase. Well-defined spin excitations exhibiting distinct dispersion have been detected. The results contribute to the general understanding of the magnetic interactions in YbCo₂Si₂.