Ordering and Excitations in the Field-Induced Magnetic Phase of Cs_3Cr_2Br_9

TL;DR

This study investigates the magnetic ordering and excitations in Cs_3Cr_2Br_9 under high magnetic fields, revealing incommensurate structures, hysteresis, and a persistent excitation gap, advancing understanding of field-induced magnetic phases.

Contribution

It provides detailed neutron scattering analysis of the magnetic order and excitations in Cs_3Cr_2Br_9, including the fully determined structure and behavior of the excitation gap under magnetic fields.

Findings

Incommensurate magnetic order with hysteresis observed.

The magnetic structure is fully determined.

The lowest excitation branch remains gapped above H_c1.

Abstract

Field-induced magnetic order has been investigated in detail in the interacting spin 3/2 dimer system Cs_3Cr_2Br_9. Elastic and inelastic neutron scattering measurements were performed up to H = 6 T, well above the critical field H_c1 = 1.5 T. The ordering displays incommensurabilities and a large hysteresis before a commensurate structure is reached. This structure is fully determined. Surprisingly, the lowest excitation branch never closes. Above H_c1, the gap increases slowly with field. An analysis in terms of projected pseudo-spin is given.