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arXiv · 1506.04545

Quadrupole Order in the Frustrated Pyrochlore Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$

H. Takatsu·S. Onoda·S. Kittaka·A. Kasahara·Y. Kono·T. Sakakibara·Y. Kato·B. Fåk·J. Ollivier·J. W. Lynn·T. Taniguchi·M. Wakita·H. Kadowaki
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Abstract

A hidden order that emerges in the frustrated pyrochlore Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ with $T_{\text{c}}=0.53$ K is studied using specific heat, magnetization, and neutron scattering experiments on a high-quality single crystal. Semi-quantitative analyses based on a pseudospin-1/2 Hamiltonian for ionic non-Kramers magnetic doublets demonstrate that it is an ordered state of electric quadrupole moments. The elusive spin liquid state of the nominal Tb$_2$Ti$_2$O$_7$ is most likely a U(1) quantum spin-liquid state.

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H. Takatsu, S. Onoda, S. Kittaka, A. Kasahara, Y. Kono, T. Sakakibara, Y. Kato, B. Fåk, J. Ollivier, J. W. Lynn, T. Taniguchi, M. Wakita, H. Kadowaki. 2016-04-17. Quadrupole Order in the Frustrated Pyrochlore Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$. https://doi.org/10.1103/physrevlett.116.217201

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