Rashba interfaces yield efficient spin-charge interconversion and give rise to nonreciprocal transport phenomena. Here, we report magnetotransport experiments in few-nanometer-thick films of PdCoO, a delafossite oxide known to display a large Rashba splitting and surface ferromagnetism. By analyzing the angle dependence of the first- and second-harmonic longitudinal and transverse resistivities, we identify a Rashba-driven unidirectional magnetoresistance that competes with the anomalous Nernst effect below the Curie point. We estimate a Rashba coefficient of 0.75 ± 0.3 eV Å and argue that our results qualify delafossites as a new family of oxides for nanospintronics and spin-orbitronics, beyond perovskite materials.
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http://dx.doi.org/10.1021/acs.nanolett.1c02756 | DOI Listing |
Sci Adv
January 2025
Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China.
Electromagnetic wave propagation in three-dimensional (3D) space typically suffers omnidirectional scattering when encountering obstacles. In this study, we used Chern vectors to construct a topological heterostructure, where large-volume nonreciprocal topological transport in 3D is achieved. The shape of the cross section in the heterostructure can be arbitrary designed, and we experimentally observed the distinctive cross-shaped field pattern transport, nonreciprocal energy harvesting, and the remarkable ability of electromagnetic wave to traverse obstacles and abrupt structure changes without encountering reflections in 3D space.
View Article and Find Full Text PDFNat Mater
January 2025
School of Physics and Astronomy, Beijing Normal University, Beijing, China.
The coherent spin waves, magnons, can propagate without accompanying charge transports and Joule heat dissipation. Room-temperature and long-distance spin waves propagating within nanoscale spin channels are considered promising for integrated magnonic applications, but experimentally challenging. Here we report that long-distance propagation of chiral magnonic edge states can be achieved at room temperature in manganite thin films with long, antiferromagnetically coupled spin spirals (millimetre length) and low magnetic Gilbert damping (~3.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Time-reversal symmetry breaking of a topological insulator phase generates zero-field edge modes which are the hallmark of the quantum anomalous Hall effect (QAHE) and of possible value for dissipation-free switching or non-reciprocal microwave devices. But present material systems exhibiting the QAHE, such as magnetically doped bismuth telluride and twisted bilayer graphene, are intrinsically unstable, limiting their scalability. A pristine magnetic oxide at the surface of a TI would leave the TI structure intact and stabilize the TI surface, but epitaxy of an oxide on the lower-melting-point chalcogenide presents a particular challenge.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510641, China.
Linear optical diffraction of light is a basic natural phenomenon subject to a long history study and it obeys the well-known reciprocity in transport. In this work we report observation of synergistic nonreciprocal linear and nonlinear diffraction of a Ti:sapphire femtosecond laser beam against a periodic poled lithium niobate (PPLN) thin plate nonlinear grating with a front surface corrugated with a shallow grating of a depth only 67 nm and a smooth back surface. A high peak power pump laser beam shining upon the geometrically asymmetric nonlinear grating from either the front surface and back surface will both cause significant second-order nonlinear (2nd-NL) Raman-Nath diffraction and Cerenkov radiation, in addition to apparent linear optical diffraction and modest third-order nonlinear (3rd-NL) spectral broadening.
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