The recently discovered material Cs3Fe2Br9 contains Fe2Br9 bi-octahedra forming triangular layers with hexagonal stacking along the c axis. In contrast to isostructural Cr-based compounds, the zero-field ground state is not a nonmagnetic S=0 singlet-dimer state. Instead, the Fe2Br9 bi-octahedra host semiclassical S=5/2 Fe3+ spins with a pronounced easy-axis anisotropy along c and interestingly, the intra-dimer spins are ordered ferromagnetically. The high degree of magnetic frustration due to (various) competing intra- and inter-dimer couplings leads to a surprisingly rich magnetic phase diagram. Already the zero-field ground state is reached via an intermediate phase, and the high-field magnetization and thermal expansion data for H∥c identify ten different ordered phases. Among them are phases with constant magnetization of 1/3, respectively 1/2 of the saturation value, and several transitions are strongly hysteretic with pronounced length changes reflecting strong magnetoelastic coupling.
@article{arxiv.2106.00440,
title = {Multiple field-induced phases in the frustrated triangular magnet Cs$_3$Fe$_2$Br$_9$},
author = {D. Brüning and T. Fröhlich and D. Gorkov and I. Císařová and Y. Skourski and L. Rossi and B. Bryant and S. Wiedmann and M. Meven and A. Ushakov and S. V. Streltsov and D. Khomskii and P. Becker and L. Bohatý and M. Braden and T. Lorenz},
journal= {arXiv preprint arXiv:2106.00440},
year = {2021}
}
Comments
11 pages, 12 figures (minor corrections and 3 additional have been included in V3)