Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Frustrated Magnets - Pyrochlore Systems and Iridates
TT 3.6: Vortrag
Montag, 7. März 2016, 11:00–11:15, H20
Neutron scattering investigation of rare earth pyrochlore iridates and hafnates — •Erxi Feng1, Yixi Su1, Thomas Wolf2, and Thomas Brueckel3,1 — 1Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany — 2Institut für Festkörperphysik, Karlsruhe Institute of Technology KIT, D-76021 Karlsruhe, Germany — 3Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA- FIT, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
Pyrochlore iridates and hafnates A2B2O7 (A= rare earth ion, B=Ir, Hf), in which both the A-site and the B-site ions form corner-sharing tetrahedra, have recently attracted considerable research interests due to the presence of both strong spin-orbit coupling and geometrical frustration. A2B2O7 displays an intriguing metal-to-insulator transition (MIT) driven by both thermodynamics and chemical pressure, which is suggested to coincide with possible magnetic order at the Ir4+ site. Moreover, the two sublattices of A3+ and Ir4+ might be magnetically coupled thus leading to novel magnetic behaviors. As a counterpart, A2B2O7 compounds are insulator and the Hf4+ ion is nonmagnetic. Pyrochlore iridates and hafnates powders with light rare earth Pr and Nd were synthesized by standard solid state reaction. Combined X-ray and neutron powder diffraction refinements suggest that the samples are stoichiometric. In this presentation, our recent investigations of the magnetic ground states of these compounds via comprehensive neutron scattering techniques will be reported.