Novel magnetic phase in a weakly ordered spin-1/2 chain antiferromagnet Sr${}_2$CuO${}_3$

Abstract

We present the magnetic phase diagram of a spin-1/2 chain antiferromagnet Sr${}_2$CuO${}_3$ studied by ultrasound phase-sensitive detection technique. We observe an enhanced effect of external magnetic field on the ordering temperature of the system, which is in the extreme proximity to the quantum critical point. Inside the Néel ordered phase, we detect an additional field-induced continuous phase transition, which is unexpected for a collinear Heisenberg antiferromagnet. This transition is accompanied by softening of magnetic excitation mode observed by electron-spin resonance, which can be associated with a longitudinal (amplitude) mode of the order parameter in a weakly-coupled system of spin-1/2 chains. These results suggest transition from a transverse collinear antiferromagnet to an amplitude-modulated spin density wave phase induced by magnetic field.

arXiv comment4 pages, 4 figures

References in corpus (10)

• Quantum criticality and universal scaling of a quantum antiferromagnet
• Dynamics of coupled quantum spin chains
• Reduction of ordered moment and Neel temperature of quasi one-dimensional antiferromagnets Sr2CuO3 and Ca2CuO3
• Covalent bonding and magnetism in cuprates
• Field-induced incommensurate order for the quasi-one-dimensional XXZ model in a magnetic field
• Neel order in doped quasi one-dimensional antiferromagnets
• Longitudinal Magnetic Dynamics and Dimensional Crossover in the Quasi-One-Dimensional, Spin-1/2, Heisenberg Antiferromagnet KCuF3
• Static properties of a quasi one-dimensional antiferromagnet in magnetic field
• Impurities in weakly coupled quantum spin chains Sr${}_2$CuO${}_3$ and SrCuO${}_2$
• Heisenberg Necklace Model in Magnetic Field

Cited by in corpus (1)

• Two-band Conduction and Nesting Instabilities in Superconducting Ba${}_2$CuO${}_{3+\delta }$: a First Principles Study