Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 44: Correlated Electrons: Quantum-Critical Phenomena – Experiments
TT 44.5: Talk
Tuesday, March 17, 2015, 15:00–15:15, H 3005
Neutron scattering of modulated magnetic order at the border of ferromagnetism in NbFe2 — •Philipp G Niklowitz1, Max Hirschberger2, James Poulten1, William Duncan1, Andreas Neubauer3, Petr Cermak4, Astrid Schneidewind4, Klaus Seemann5, Enrico Faulhaber5, Christian Pfleiderer3, and F Malte Grosche6 — 1Dept of Physics, Royal Holloway, University of London, Egham, UK — 2Dept of Physics, Princeton University, Princeton, USA — 3Fakultät für Physik, TU München, Garching, Germany — 4JCNS at MLZ, Forschungszentrum Jülich GmbH, Garching, Germany — 5MLZ, TU München, Garching, Germany — 6Cavendish Laboratory, University of Cambridge, Cambridge, UK
The border of ferromagnetism in the C14 Laves phase NbFe2 is characterised by non-Fermi liquid properties consistent with ferromagnetic quantum criticality [1], but the ferromagnetic quantum critical point appears to be masked by modulated magnetic order (MMO).[2] With our elastic neutron scattering studies of three single-crystalline Nb1−yFe2+y samples ranging from Fe-rich composition to a nearly stoichiometric sample we have directly determined the ordering wave vector q1 of MMO. A weak T and H and considerable y dependence of q1 is observed. Our inelastic neutron data is dominated by strong quasielastic scattering in the vicinity of (002) and contains further features near q1. The results indicate that NbFe2 could display the theoretically predicted scenario of a ferromagnetic quantum critical point, which is masked by emerging modulated magnetic order.
[1] M. Brando et al., PRL 101, 026401 (2008).
[2] D. Rauch et al., arXiv1312.2357