Magnetic phase diagram of A₂[FeCl₅(H₂O)] ( A= K, Rb, NH₄)

Journal Article · 01 April 2022 · Journal of Magnetism and Magnetic Materials

DOI: https://doi.org/10.1016/j.jmmm.2022.169302 · OSTI ID:1894838

Lee, Minseong  ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Here, erythrosiderites with the formula A₂FeX₅∙H₂O, where A = Rb, K, and (NH₄) and X = Cl and Br are intriguing systems that possess various magnetic and electric phases, as well as multiferroic phases in which magnetism and ferroelectricity are coupled. In this report, we study the magnetic phase diagram of erythrosiderites as a function of superexchange interactions and magnetic anisotropies. To this end, we perform classical Monte Carlo simulations on magnetic Hamiltonians that contain five different superexchange interactions with single-ion anisotropies. Our phase diagram contains all magnetic ground states that have been experimentally observed in these materials. We argue that the ground states can be explained by varying the ratio of $$\frac{J_4}{J_2}$$. For $$\frac{J_4}{J_2}$$ > 0.95 a cycloidal spins structure is stabilized as observed in (NH₄)₂FeCl₅∙H₂O and otherwise a collinear spin structure is stabilized as observed in (K,Rb)₂FeCl₅ ∙H₂O. We also show that the difference in the single-ion anisotropy along a- and c- axes is essential to stabilize the intermediate state observed in (NH)₂FeCl₅∙H₂O.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC). Office of Basic Energy Sciences (BES)
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1894838
• Alternate ID(s): OSTI ID: 1862878
• Report Number(s): LA-UR-21-28901
• Journal Information: Journal of Magnetism and Magnetic Materials, Journal Name: Journal of Magnetism and Magnetic Materials Vol. 555; ISSN 0304-8853
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English