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S= 12 quantum critical spin ladders produced by orbital ordering in Ba2CuTeO6
A. Gibbs S., A. Yamamoto, A. Yaresko N., K. Knight S., H. Yasuoka, M. Baenitz, P. Saines J., J. Hester R., D. HashizumeShow More
Published in
2017
Volume: 95

Issue: 10
Abstract
The ordered hexagonal perovskite Ba2CuTeO6 hosts weakly coupled S=12 spin ladders produced by an orbital ordering of Cu2+. The magnetic susceptibility $\chi$(T) of Ba2CuTeO6 is well described by that expected for isolated spin ladders with exchange coupling of J≈86K but shows a deviation from the expected thermally activated behavior at low temperatures below T∗≈25K. An anomaly in $\chi$(T), indicative of magnetic ordering, is observed at Tmag=16K. No clear signature of long-range ordering, however, is captured so far in NMR 1/T1, specific heat or neutron diffraction measurements at and below Tmag. The marginal magnetic transition, indicative of strong quantum fluctuations, is evidence that Ba2CuTeO6 is in very close proximity to a quantum critical point between magnetically ordered and spin-gapped phases controlled by interladder couplings.