1. Topological magnetic order and superconductivity in EuRbFe$_4$As$_4$
- Author
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Hemmida, M., Winterhalter-Stocker, N., Ehlers, D., von Nidda, H. -A. Krug, Yao, M., Bannies, J., Rienks, E. D. L., Kurleto, R., Felser, C., Büchner, B., Fink, J., Gorol, S., Förster, T., Arsenijevic, S., Fritsch, V., and Gegenwart, P.
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Strongly Correlated Electrons - Abstract
We study single crystals of the magnetic superconductor EuRbFe$_4$As$_4$ by magnetization, electron spin resonance (ESR), angle-resolved photoemission spectroscopy (ARPES) and electrical resistance in pulsed magnetic fields up to 630 kOe. The superconducting state below 36.5 K is almost isotropic and only weakly affected by the development of Eu$^{2+}$ magnetic order at 15 K. On the other hand, for the external magnetic field applied along the c-axis the temperature dependence of the ESR linewidth reveals a Berezinskii-Kosterlitz-Thouless topological transition below 15 K. This indicates that Eu$^{2+}$-planes are a good realization of a two-dimensional XY-magnet, which reflects the decoupling of the Eu$^{2+}$ magnetic moments from superconducting FeAs-layers.
- Published
- 2020
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