Effect of antifluorite layer on the magnetic order in Eu-based 1111 compounds, EuTAsF (T = Zn, Mn, and Fe)
| Autor: | Igor V. Plokhikh, Alexander A. Tsirlin, Dmitry D. Khalyavin, Henry E. Fischer, Andrei V. Shevelkov, Arno Pfitzner |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Physical Chemistry Chemical Physics. 25:4862-4871 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/d2cp04863a |
| Popis: | The 1111 compounds with an alternating sequence of fluorite and antifluorite layers serve as structural hosts for the vast family of Fe-based superconductors. Here, we use neutron powder diffraction and density-functional-theory (DFT) band-structure calculations to study magnetic order of Eu2+ in the [EuF]+ fluorite layers depending on the nature of the [TAs]- antifluorite layer that can be non-magnetic semiconducting (T = Zn), magnetic semiconducting (T = Mn), or magnetic metallic (T = Fe). Antiferromagnetic transitions at TN ~ 2.4 - 3 K due to an ordering of the Eu2+ magnetic moments were confirmed in all three EuTAsF compounds. Whereas in EuTAsF (T = Zn and Mn), the commensurate k1 = (1/2 1/2 0) stripe order pattern with magnetic moments within the ab-plane is observed, the order in EuFeAsF is incommensurate with k = (0 0.961(1) 1/2) and represents a cycloid of Eu2+ magnetic moments confined within the bc-plane. Additionally, the Mn2+ sublattice in EuMnAsF features a robust G-type antiferromagnetic order that persists at least up to room temperature, with magnetic moments along the c-direction. Although DFT calculations suggest stripe antiferromagnetic order in the Fe-sublattice of EuFeAsF as the ground state, neutron diffraction reveals no evidence of long-range magnetic order associated with Fe. We show that the frustrating interplane interaction J3 between the adjacent [EuF]+ layers is comparable with in-plane J1-J2 interactions already in the case of semiconducting fluorite layers [TAs]- (T = Zn and Mn) and becomes dominant in the case of the metallic [FeAs]- ones. The latter, along with a slight orthorhombic distortion, is proposed to be the origin of the incommensurate magnetic structure observed in EuFeAsF. |
| Databáze: | OpenAIRE |
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