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In the past years, magnetism-driven ferroelectricity and gigantic magnetoelectric effects have been reported for a number of frustrated magnets with spiral magnetic orders. Such materials are of high current interest due to their potential for spintronics and low-power magnetoelectric devices. However, their low magnetic order temperatures (typically < 100 K) greatly restrict their fields of application.
Recently, we have established that chemical disorder is a powerful tool that can be used to stabilize magnetic spiral phases up to 310 K [1]. Here we explore the design space opened up by this novel stabilization mechanism, recently rationalized in terms of random magnetic exchanges [2]. We show that in CuFe-based layered perovskites Tspiral can be further increased up to 400 K, and we reveal a scaling law between this quantity and the spiral wave vector [3]. This linear relationship ends at a paramagnetic–collinear–spiral multicritical point, which defines the highest spiral-order temperatures that can be achieved in this kind of materials. Based on our findings, we propose a general set of rules for designing magnetic spirals in layered perovskites using external pressure, chemical substitutions and/or epitaxial strain, which should guide future efforts to engineering spiral phases with order temperatures suitable for technological applications.
[1] M. Morin et al., Nature Communications 7, 13758 (2016)
[2] A. Scaramucci et al., Physical Review X, 8, 011005 (2018)
[3] T. Shang et al., Science Advances, 4, eaau6386 (2018)
