German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities

Critical scattering in classical and nearly quantum critical systems

17 Sept 2018, 16:30

1h 30m

Fakultät für Maschinenwesen der Technischen Universität München

Poster P4 Magnetism and quantum phenomena Poster session 1

Speaker

Mr Heiko Trepka (MPI für Festkörperforschung, Stuttgart & MPG Außenstelle am MLZ, Garching)

Description

We report on a study of critical scattering in classical and nearly quantum critical antiferromagnets (AFs). The energy width of the critical scattering was determined by high-resolution neutron spin-echo at TRISP at the MLZ. The classical systems studied include the s=5/2 AFs MnF2 and Rb2MnF4 with quasi 2D and 3D spin interactions, respectively. Discrepancies between experiment and theory observed in previous three-axis studies could be resolved by our high-resolution measurement. For a study of quantum critical systems, we chose the Ce Cu6-x Aux series, which has a quantum critical point at x=0.1 and shows AF ordering for larger x. First measurements at Ce Cu5.8 Au0.2 (TN=0.22K) show a hitherto unexplained dynamical critical exponent.