Polar ferromagnet induced by fluorine positioning in isomeric layered copper halide perovskites

Ceng Han, Jason A. McNulty, Alasdair J. Bradford, Alexandra M. Z. Slawin, Finlay D. Morrison, Steve Lee, Philip Lightfoot*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
4 Downloads (Pure)


We present the influence of positional isomerism on the crystal structure of fluorobenzylammonium copper (II) chloride perovskites A2CuCl4, by incorporating ortho, meta and para- fluorine substitution in the benzylamine structure. Two-dimensional (2D) polar ferromagnet (3-FbaH)2CuCl4 (3-FbaH+ = 3-fluorobenzylammonium) is successfully obtained, which crystallizes in a polar orthorhombic space group Pca21 at room temperature. In contrast, both (2-FbaH)2CuCl4 (2-FbaH+ = 2-fluorobenzylammonium) and (4-FbaH)2CuCl4 (4-FbaH+ = 4-fluorobenzylammonium) crystallize in centrosymmetric space groups P21/c and Pnma at room temperature, respectively, displaying significant differences in crystal structures. These differences indicate that the position of the fluorine atom is a driver for the polar behaviour in (3-FbaH)2CuCl4. Preliminary magnetic measurements confirm that these three perovskites possess dominant ferromagnetic interactions within the inorganic [CuCl4] layers. Therefore, (3-FbaH)2CuCl4 is a polar ferromagnet, with potential as a type I multiferroic. This work is expected to promote further development of high performance 2D copper (II) halide perovskite multiferroic materials.
Original languageEnglish
Pages (from-to)3230-3239
JournalInorganic Chemistry
Issue number7
Early online date9 Feb 2022
Publication statusPublished - 21 Feb 2022


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