Journal Article

PreJuSER-22702

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Higgs transition from a manetic Coulomb liquid to a ferromagnet in Yb2Ti2O7

Chang, L.-J. ; Onoda, S. ; Su, Y.FZJ* ; Kao, Y.-J. ; Tsuei, K.-D. ; Yasui, Y. ; Kakurai, K. ; Lees, M. R.

2012
Nature Publishing Group London

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Please use a persistent id in citations: doi:10.1038/ncomms1989

Abstract: In a class of frustrated magnets known as spin ice, magnetic monopoles emerge as classical defects and interact via the magnetic Coulomb law. With quantum-mechanical interactions, these magnetic charges are carried by fractionalized bosonic quasi-particles, spinons, which can undergo Bose-Einstein condensation through a first-order transition via the Higgs mechanism. Here, we report evidence of a Higgs transition from a magnetic Coulomb liquid to a ferromagnet in single-crystal Yb(2)Ti(2)O(7). Polarized neutron scattering experiments show that the diffuse [111]-rod scattering and pinch-point features, which develop on cooling are suddenly suppressed below T(C)~0.21 K, where magnetic Bragg peaks and a full depolarization of the neutron spins are observed with thermal hysteresis, indicating a first-order ferromagnetic transition. Our results are explained on the basis of a quantum spin-ice model, whose high-temperature phase is effectively described as a magnetic Coulomb liquid, whereas the ground state shows a nearly collinear ferromagnetism with gapped spin excitations.

Keyword(s): Basic research (1st) ; Others (1st) ; Magnetism (2nd) ; J

Note: We thank J.S. Gardner, B.D. Gaulin and A. Yaouanc for discussions. We thank Harald Schneider for technical supports in the neutron scattering experiments. We acknowledge Chih-Wen Pao and other staff of BL07A of the NSRRC who helped perform the EXAFS measurements. This work is partially supported by National Science Council, Taiwan, under grants no. NSC 96-2739-M-213-001, NSC 99-2112M-007-020 (L.J.C.), NSC 100-2112-M-002-013-MY3, NSC-99-2120-M-002-005 (Y.J.K.), by NTU under grant no. 10R80909-4 (Y.J.K.), and by grants-in-aid for Scientific Research under grant no. 21740275 and no. 24740253 from Japan Society for the Promotion of Science (S.O.) and under grant no. 19052006 (S.O.) and no. 19052004 (K.K.) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.

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Contributing Institute(s):

1. Streumethoden (PGI-4)
2. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
3. Streumethoden (JCNS-2)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)

Experiment(s):

1. DNS: Diffuse scattering neutron time of flight spectrometer (NL6S)

Appears in the scientific report 2012

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