The cubic perovskite SrFeO3 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 Sr2FeO4, so a reinvestigation of the bilayer material Sr3Fe2O7, 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 SrFeO3. In particular, at least one phase is apparently multiple-q, and the qs are not observed to vary among the phases. Since Sr3Fe2O7 has only two possible orientations for its propagation vector, some of the phases are likely exotic multiple-q order, and it is possible to fully detwin all phases and more readily access their exotic physics.
@article{arxiv.2309.15594,
title = {Rich Magnetic Phase Diagram of Putative Helimagnet Sr$_3$Fe$_2$O$_7$},
author = {Nikita D. Andriushin and Justus Grumbach and Jung-Hwa Kim and Manfred Reehuis and Yuliia V. Tymoshenko and Yevhen A. Onykiienko and Anil Jain and W. Andrew MacFarlane and Andrey Maljuk and Sergey Granovsky and Andreas Hoser and Vladimir Pomjakushin and Jacques Ollivier and Mathias Doerr and Bernhard Keimer and Dmytro S. Inosov and Darren C. Peets},
journal= {arXiv preprint arXiv:2309.15594},
year = {2023}
}