Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 14: Cooperative Phenomena: Spin Structures and Magnetic Phase Transitions
MA 14.6: Vortrag
Dienstag, 6. September 2022, 11:00–11:15, H47
identification of a new hidden-order phase in the magnetic phase diagram of Ce3Pd20Si6 — •F. Mazza1, P. Y. Portnichenko2, P. Steffens3, M. Boehm3, E. S. Choi4, M. Nikolo5, S. Paschen1, and D. S. Inosov2 — 1TU Wien, Austria — 2TU Dresden, Germany — 3ILL, Grenoble, France — 4Florida State University, Tallahassee, USA — 5St. Louis University, USA
Magnetically hidden order is a hypernym for electronic ordering phenomena whose microscopic symmetry cannot be revealed with conventional neutron or x-ray diffraction. In a handful of f-electron systems, the ordering of odd-rank multipoles leads to order parameters with a vanishing neutron cross-section. Among them, Ce3Pd20Si6 is known for its unique phase diagram exhibiting two distinct multipolar-ordered ground states (phases II and II′), separated by a field-driven quantum phase transition. Using torque magnetometry at subkelvin temperatures, here we find another phase transition at higher fields above 12 T, which appears only for low-symmetry magnetic field directions. While the order parameter remains unknown, this discovery renders Ce3Pd20Si6 the first known material with two metamultipolar phase transitions. They are both clearly manifested in the magnetic-field dependence of the field-induced (111) Bragg intensities measured with neutron scattering for B∥[112]. Furthermore, the magnetic excitation spectrum suggests that the new phase II′′ may have a different propagation vector in the vicinity of Q = (010), revealed by the minimum in the dispersion representing the Goldstone mode of this hidden-order phase.