In the article “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” Korbinian Geirhos, Boris Gross, Bertalan G. Szigeti, Andrea Mehlin, Simon Philipp, Jonathan S. White, Robert Cubitt, Sebastian Widmann, Somnath Ghara, Peter Lunkenheimer, Vladimir Tsurkan, Erik Neuber, Dmytro Ivaneyko, Peter Milde, Lukas M. Eng, Andrey O. Leonov, Sándor Bordács, Martino Poggio and István Kézsmárki report a magnetic state in GaV4Se8 which emerges exclusively in samples with mesoscale polar domains and not in polar mono-domain crystals.*
It is manifested by a sharp anomaly in the magnetic susceptibility and the magnetic torque, distinct from other anomalies observed also in polar mono-domain samples upon transitions between the cycloidal, the Néel-type skyrmion lattice and the ferromagnetic states. *
The authors ascribe this additional transition to the transformation of distinct magnetic textures, confined to polar domain walls (DW), to the ferromagnetic (FM) state. The emergence of these DW-confined magnetic states is likely driven by the mismatch of different spin spirals, hosted by the adjacent domains. A clear anomaly in the magneto-current indicates that the DW-confined magnetic states also have strong contributions to the magnetoelectric response. *
The authors expect polar DWs to commonly host such confined magnetic edge states and, thus, offer a fertile ground to explore novel forms of magnetism. *
To characterize the polar domains and to estimate the density of DWs in GaV4Se8, K. Geirhos et al. combined several complementary scanning probe microscopy techniques, including non-contact atomic force microscopy ( nc-AFM ), scanning dissipation microscopy ( SDM ), and frequency-modulated Kelvin-probe force microscopy ( KPFM ). *
In attempt to observe spin cycloidal and Néel-type skyrmion textures within polar domains of GaV4Se8, only evidenced by small-angle neutron scattering measurements so far43, the authors of the article also carried out magnetic force microscopy (MFM) measurements. A second purpose of the MFM study was to explore possible magnetic states confined to the vicinity of DWs, as reported in GaV4S8. *
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