Quantum critical fluctuations in a transverse-field Ising magnet.
J Phys Condens Matter
; 36(32)2024 May 13.
Article
in En
| MEDLINE
| ID: mdl-38684155
ABSTRACT
CoNb2O6is a model system for a spin-1/2 one-dimensional (1D) transverse-field Ising magnet (TFIM) with a rather low three-dimensional (3D) Néel ordering temperature atTN=2.95K. We studied CoNb2O6using ultrasound measurements down to 0.3 K in transverse magnetic fields applied along thebdirection. Upon entering the 3D ordered state, we observe pronounced anomalies in the transverse acoustic modec66. In particular, from 1.3 to 1.5 K and around 4.7 T, this mode reveals an almost diverging softening, which is considerably reduced at lower and higher magnetic fields. We interpret this as an influence of quantum critical fluctuations emerging from the quantum critical point (QCP) of the 1D Ising spin chains at about 4.75 T, which lies below the QCP of the 3D ordering at about 5.4 T. This is clear experimental evidence of the predicted generic phase diagram for a TFIM with superimposed 3D ordering.
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Phys Condens Matter
Year:
2024
Document type:
Article