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  Quintero-Castro, D.L.; Lake, B.; Reehuis, M.; Niazi, A.; Ryll, H.; Islam, A.T.M.N.; Fennell, T.; Kimber, S.A.J.; Klemke, B.; Ollivier, J.; Garcia Sakai, V.; Deen, P.P.; Mutka, H.: Coexistence of long- and short-range magnetic order in the frustrated magnet SrYb₂O₄. Physical Review B 86 (2012), p. 064203/1-10

10.1103/PhysRevB.86.064203
Open Access Version (externer Anbieter)

Abstract:
SrYb2O4 is a geometrically frustrated rare-earth magnet, which presents a variety of interrelated magnetic phenomena. The magnetic Yb3+ ions (J=7/2) form potentially frustrated “zigzag” chains along the c axis, arranged in a honeycomb fashion in the ab plane. Heat capacity reveals a magnetic phase transition at TN=0.9 K. The magnetic structure was solved by polarized neutron diffraction and found to be noncollinear with a reduction of the ordered spin moment from the full ionic moment. The low-energy excitations, which were measured by inelastic neutron scattering reveal diffuse scattering both above and below TN. Heat capacity and magnetocaloric effect were performed to map out the magnetic phase diagram as a function of magnetic field and temperature and show a complicated series of states. Altogether, the results suggest that the magnetic interactions in SrYb2O4 compete with each other and with the single-ion anisotropy to produce a highly degenerate ground state manifold that suppresses the magnetic order, broadens the excitations and gives rise to a complex phase diagram