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arXiv · 2309.15594

Rich Magnetic Phase Diagram of Putative Helimagnet Sr$_3$Fe$_2$O$_7$

Nikita D. Andriushin·Justus Grumbach·Jung-Hwa Kim·Manfred Reehuis·Yuliia V. Tymoshenko·Yevhen A. Onykiienko·Anil Jain·W. Andrew MacFarlane·Andrey Maljuk·Sergey Granovsky·Andreas Hoser·Vladimir Pomjakushin·Jacques Ollivier·Mathias Doerr·Bernhard Keimer·Dmytro S. Inosov·Darren C. Peets
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Abstract

The cubic perovskite SrFeO$_3$ was recently reported to host hedgehog- and skyrmion-lattice phases in a highly symmetric crystal structure which does not support the Dzyaloshinskii-Moriya interactions commonly invoked to explain such magnetic order. Hints of a complex magnetic phase diagram have also recently been found in powder samples of the single-layer Ruddlesden-Popper analog Sr$_2$FeO$_4$, so a reinvestigation of the bilayer material Sr$_3$Fe$_2$O$_7$, believed to be a simple helimagnet, is called for. Our magnetization and dilatometry studies reveal a rich magnetic phase diagram with at least 6 distinct magnetically ordered phases and strong similarities to that of SrFeO$_3$. In particular, at least one phase is apparently multiple-$\mathbf{q}$, and the $\mathbf{q}$s are not observed to vary among the phases. Since Sr$_3$Fe$_2$O$_7$ has only two possible orientations for its propagation vector, some of the phases are likely exotic multiple-$\mathbf{q}$ order, and it is possible to fully detwin all phases and more readily access their exotic physics.

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Nikita D. Andriushin, Justus Grumbach, Jung-Hwa Kim, Manfred Reehuis, Yuliia V. Tymoshenko, Yevhen A. Onykiienko, Anil Jain, W. Andrew MacFarlane, Andrey Maljuk, Sergey Granovsky, Andreas Hoser, Vladimir Pomjakushin, Jacques Ollivier, Mathias Doerr, Bernhard Keimer, Dmytro S. Inosov, Darren C. Peets. 2023-09-27. Rich Magnetic Phase Diagram of Putative Helimagnet Sr$_3$Fe$_2$O$_7$. https://doi.org/10.1103/physrevb.108.174420

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