Chiral spin spiral in synthetic antiferromagnets probed by circular dichroism in x-ray resonant magnetic scattering

Léveillé, Cyril; Flewett, Samuel; Burgos-Parra, Erick; Sassi, Yanis; Legrand, William; Ajejas, Fernando; Cros, Vincent; Reyren, Nicolas; Jaouen, N.

doi:10.1103/physrevb.104.l060402

Cited by 5 publications

(4 citation statements)

References 42 publications

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“…In the experiment of Ref. [48], the helical state periodicity was found to be approximately 190 nm. With a typically a few tenths of a nm, this is a much larger periodicity than that considered in this paper.…”

Section: B Magnetic Insulatormentioning

confidence: 89%

“…DMI originates with SOC, and is present in chiral magnets, which break inversion symmetry [31,43] and in magnetic monolayers on top of heavy metals [32,44]. Helical states have been observed in chiral magnets [43], in ultrathin films grown on heavy metals [45,46], in van der Waals materials [47], and in synthetic antiferromagnets [48].…”

Section: B Magnetic Insulatormentioning

confidence: 99%

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Topological superconductivity mediated by magnons of helical magnetic states

Mæland,

Abnar,

Benestad

et al. 2023

Phys. Rev. B

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We recently showed that spin fluctuations of noncoplanar magnetic states can induce topological superconductivity in an adjacent normal metal [Maeland et al., Phys. Rev. Lett. 130, 156002 (2023)]. The noncolinear nature of the spins was found to be essential for this result, while the necessity of noncoplanar spins was unclear. In this paper we show that magnons in coplanar, noncolinear magnetic states can mediate topological superconductivity in a normal metal. Two models of the Dzyaloshinskii-Moriya interaction are studied to illustrate the need for a sufficiently complicated Hamiltonian describing the magnetic insulator. The Hamiltonian, in particular the specific form of the Dzyaloshinskii-Moriya interaction, affects the magnons and by extension the effective electron-electron interaction in the normal metal. Symmetry arguments are applied to complement this discussion. We solve a linearized gap equation in the case of weak-coupling superconductivity. The result is a time-reversal-symmetric topological superconductor, as confirmed by calculating the topological invariant. In analogy with magnon-mediated superconductivity from antiferromagnets, Umklapp scattering enhances the critical temperature of superconductivity for certain Fermi momenta.

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Section: B Magnetic Insulatormentioning

confidence: 89%

Section: B Magnetic Insulatormentioning

confidence: 99%

Topological superconductivity mediated by magnons of helical magnetic states

Mæland,

Abnar,

Benestad

et al. 2023

Phys. Rev. B

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“…Up to date, the diffraction geometry was mainly utilized to study helical and skyrmion satellites of the anomalous reflection (001) in Cu 2 OSeO 3 . Alternatively, for thin films and multilayers the specular [29,44,45] and multilayer Bragg sheet [32,33,46,47] geometries are utilized to detect magnetic satellites of the corresponding reflection.…”

Section: Introductionmentioning

confidence: 99%

Chiral surface spin textures in Cu$_2$OSeO$_3$ unveiled by soft x-ray scattering in specular reflection geometry

Ukleev,

Luo,

Abrudan

et al. 2022

Preprint

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Resonant elastic soft x-ray magnetic scattering (XRMS) is a powerful tool to explore long-periodic spin textures in single crystals. However, due to the limited momentum transfer range imposed by long wavelengths of photons in the soft x-ray region, Bragg diffraction is restricted to crystals with the large lattice parameters. Alternatively, small angle x-ray scattering has been involved in the soft energy x-ray range which, however, brings in difficulties with the sample preparation that involves focused ion beam milling to thin down the crystal to below a few hundred nm thickness. We show how to circumvent these restrictions by using XRMS in specular reflection from a sub-nanometer smooth crystal surface. The method allows observing diffraction peaks from the helical and conical spin modulations at the surface of a Cu2OSeO3 single crystal and probing their corresponding chirality as contributions to the dichroic scattered intensity. The results suggest a promising way to carry out XRMS studies on plethora of noncentrosymmetric systems hitherto unexplored with soft x-rays due to the absence of the commensurate Bragg peaks in the available momentum transfer range.

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“…Because the AT in our framework is completely general, it can capture the effects of charge and magnetic sources of scattering. Applications to nanostructures in multiferroic heterostructures [45] or antiferromagnetic skyrmions [46] could probe their 3D PHYSICAL REVIEW LETTERS 129, 247601 (2022)…”

mentioning

confidence: 99%