Speaker
Pascale Deen
(European Spallation Source ESS AB)
Description
The search for new states of matter is a fundamental theme of condensed matter science. Frustrated magnetic materials are promising candidates for new states because lattice geometry suppresses conventional magnetic dipole order. Frustration thus drives novel emergent states. Classical spins on the 3D triangular hyperkagome lattice have long been considered ideal for novel states yet have provided few examples.
Gd3Ga5O12 is the canonical frustrated magnet since the compound does not order via the pervasive “order by disorder” mechanism down to the lowest temperatures probed, 25 mK [1 and ref. therein]. Short-range correlations, determined via neutron diffraction, have long been assumed to originate from near neighbour short-range interactions [1]. However in recent work an emergent spin state of decagon looped structures at the lowest temperatures has been uncovered [2,3]. These emergent decagon spin loops remain dominant when attempting to polarise the spin structure by a large applied magnetic field [4]. Neutron inelastic scattering shows a dominant contribution at large momentum transfers from a band of almost dispersionless excitations that correspond to the spin waves localized on ten site rings, expected on the basis of nearest neighbor exchange interaction [4]. These result illustrate the richness and diversity that arise from frustrated exchange on the three-dimensional hyperkagome lattice.
[1] O. A. Petrenko, C. Ritter, M. Yethiraj, D. McK Paul, Phys. Rev. Lett. 80, 4570 (1998).
[2] J. A. M. Paddison, A. L. Goodwin, Phys. Rev. Lett. 108, 017204 (2012).
[3] P. P. Deen, O. Florea, E. Lhotel, and H. Jacobsen, Phys. Rev. B 91, 014419 (2015)
[4] N. d’Ambrumenil, O.!A. Petrenko, H. Mutka, and P.!P. Deen, Phys. Rev. Lett. 114, 227203 (2015)
Primary author
Pascale Deen
(European Spallation Source ESS AB)
