Character of magnetic excitations in a quasi-one-dimensional antiferromagnet near the quantum critical points: Impact on magneto-acoustic properties

Abstract

We report results of magneto-acoustic studies in the quantum spin-chain magnet NiCl${}_2$-4SC(NH${}_2$)${}_2$ (DTN) having a field-induced ordered antiferromagnetic (AF) phase. In the vicinity of the quantum critical points (QCPs) the acoustic $c_{33}$ mode manifests a pronounced softening accompanied by energy dissipation of the sound wave. The acoustic anomalies are traced up to $T>T_N$, where the thermodynamic properties are determined by fermionic magnetic excitations, the "hallmark" of one-dimensional (1D) spin chains. On the other hand, as established in earlier studies, the AF phase in DTN is governed by bosonic magnetic excitations. Our results suggest the presence of a crossover from a 1D fermionic to a 3D bosonic character of the magnetic excitations in DTN in the vicinity of the QCPs.

5 pages, 4 figures. Accepted for publication by Phys. Rev B

References in corpus (3)

• Dimensional reduction at a quantum critical point
• Bose-Einstein Condensation of Magnons in Cs2CuCl4
• Universal temperature dependence of the magnetization of gapped spin chains

Cited by in corpus (5)

• Low-Temperature Heat Transport in the Low-Dimensional Quantum Magnet NiCl_{2}-4SC(NH_{2})_{2}
• Ultrasonic investigations of spin-ices Dy${}_2$Ti${}_2$O${}_7$ and Ho${}_2$Ti${}_2$O${}_7$ in and out of equilibrium
• Effective S=1/2 description of the S=1 chain with strong easy plane anisotropy
• Antiferromagnet with two coupled antiferromagnetic sublattices in a magnetic field
• Bose-Einstein Condensation of Magnons in NiCl2-4SC(NH2)2