paper

Temperature and composition phase diagram in the iron-based ladder compounds Ba1-xCsxFe2Se3

arXiv:1503.08129

Abstract

We investigated the iron-based ladder compounds (Ba,Cs)Fe $_{2}$ Se $_{3}$ . Their parent compounds, BaFe $_{2}$ Se $_{3}$ and CsFe $_{2}$ Se $_{3}$ , have different space groups, formal valences of Fe and magnetic structures. Electrical resistivity, specific heat, magnetic susceptibility, X-ray diffraction and powder neutron diffraction measurements were conducted to obtain temperature and composition phase diagram of this system. Block magnetism observed in BaFe $_{2}$ Se $_{3}$ is drastically suppressed with Cs doping. In contrast, stripe magnetism observed in CsFe $_{2}$ Se $_{3}$ is not so fragile against Ba doping. New type of magnetic structure appears in intermediate compositions, which is similar to stripe magnetism of CsFe $_{2}$ Se $_{3}$ , but inter-ladder spin configuration is different. Intermediate compounds show insulating behavior, nevertheless finite $T$ -linear contribution in specific heat was obtained at low temperatures.

12 pages, 13 figures