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End date: 2022 × Start date: 2020 × Type: Text × Subject: Anisotropy × WGL Institute: IFWD ×

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Now showing 1 - 3 of 3
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    Strong anisotropy of the electron-phonon interaction in NbP probed by magnetoacoustic quantum oscillations
    (Woodbury, NY : Inst., 2020) Schindler, Clemens; Gorbunov, Denis; Zherlitsyn, Sergei; Galeski, Stanislaw; Schmidt, Marcus; Wosnitza, Jochen; Gooth, Johannes
    In this study, we report on the observation of de Haas-van Alphen-type quantum oscillations (QOs) in the ultrasound velocity of NbP as well as "giant QOs"in the ultrasound attenuation in pulsed magnetic fields. The difference in the QO amplitude for different acoustic modes reveals a strong anisotropy of the effective deformation potential, which we estimate to be as high as 9eV for certain parts of the Fermi surface. Furthermore, the natural filtering of QO frequencies and the tracing of the individual Landau levels to the quantum limit allows for a more detailed investigation of the Fermi surface of NbP, as was previously achieved by means of analyzing QOs observed in magnetization or electrical resistivity. © 2020 authors. Published by the American Physical Society.
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    Tunable chirality of noncentrosymmetric magnetic Weyl semimetals in rare-earth carbides
    ([London] : Nature Publishing Group, 2022) Ray, Rajyavardhan; Sadhukhan, Banasree; Richter, Manuel; Facio, Jorge I.; van den Brink, Jeroen
    Even if Weyl semimetals are characterized by quasiparticles with well-defined chirality, exploiting this experimentally is severely hampered by Weyl lattice fermions coming in pairs with opposite chirality, typically causing the net chirality picked up by experimental probes to vanish. Here, we show this issue can be circumvented in a controlled manner when both time-reversal- and inversion symmetry are broken. To this end, we investigate chirality disbalance in the carbide family RMC2 (R a rare-earth and M a transition metal), showing several members to be Weyl semimetals. Using the noncentrosymmetric ferromagnet NdRhC2 as an illustrating example, we show that an odd number of Weyl nodes can be stabilized at its Fermi surface by properly tilting its magnetization. The chiral configuration endows a topological phase transition as the Weyl node transitions across the Fermi sheets, which triggers interesting chiral electromagnetic responses. Further, the tilt direction determines the sign of the resulting net chirality, opening up a simple route to control its sign and strength.
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    Anisotropic fractal magnetic domain pattern in bulk Mn1.4PtSn
    (Woodbury, NY : Inst., 2020) Sukhanov, A.S.; Zuniga Cespedes, B.E.; Vir, P.; Cameron, A.S.; Heinemann, A.; Martin, N.; Chaboussant, G.; Kumar, V.; Milde, P.; Eng, L.M.; Felser, C.; Inosov, D.S.
    The tetragonal compound Mn1.4PtSn with D2d symmetry recently attracted attention as the first known material that hosts magnetic antiskyrmions, which differ from the skyrmions known so far by their internal structure. The latter have been found in a number of magnets with the chiral crystal structure. In previous works, the existence of antiskyrmions in Mn1.4PtSn was unambiguously demonstrated in real space by means of Lorentz transmission electron microscopy on thin-plate samples (∼100 nm thick). In the present study, we used small-angle neutron scattering and magnetic force microscopy to perform reciprocal- and real-space imaging of the magnetic texture of bulk Mn1.4PtSn single crystals at different temperatures and in applied magnetic field. We found that the magnetic texture in the bulk differs significantly from that of thin-plate samples. Instead of spin helices or an antiskyrmion lattice, we observe an anisotropic fractal magnetic pattern of closure domains in zero field above the spin-reorientation transition temperature, which transforms into a set of bubble domains in high field. Below the spin-reorientation transition temperature the strong in-plane anisotropy as well as the fractal self-affinity in zero field is gradually lost, while the formation of bubble domains in high field remains robust. The results of our study highlight the importance of dipole-dipole interactions in thin-plate samples for the stabilization of antiskyrmions and identify criteria which should guide the search for potential (anti)skyrmion host materials. Moreover, they provide consistent interpretations of the previously reported magnetotransport anomalies of the bulk crystals. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by the Max Planck Society.