The recent discovery of pressure-induced superconductivity in the iron-based spin ladders has added a new flavor to the study of iron-based superconductivity. On one hand, they have a quasi-one-dimensional structure and on the other – they are insulating at ambient conditions. Hence they appear to be more like cuprates than the other iron-based superconductors. Moreover, since these compounds do not require doping, they open an avenue to study the interplay of superconductivity and magnetism without the introduction of any disorder.
The exact nature of the magnetic ground states and their evolution has been a focus of intense studies and recently, through the use of multiple techniques we have answered some of the issues relating to the magnetic and crystal structure of these compounds.
In the case of the sulfur-end compound BaFe2S3, we have resolved the discrepancies of the previously reported anomalous jumps and have provided a consistent picture of the evolution of the magnetism with pressure.
Find out more at Phys. Rev. B 98, 180402(R)
More recently, for the selenium-end compound, BaFe2Se3, a detailed phase diagram shown above was determined. In contrast to the sulfur-end compound, there exists an abrupt structural transition. Nevertheless, the modifications of magnetic ordering temperature and ordered moment size remain smooth throughout the whole pressure range. Even more strikingly, the exotic block magnetism (antiferromagnetically coupled ferromagnetic clusters) remains robust across the transition and is stable in the whole studied pressure range.
Find out more at Phys. Rev. B 100, 214511