We present spatially resolved measurements of the magnon temperature in a magnetic insulator subject to a thermal gradient. Our data reveal an unexpectedly close correspondence between the spatial dependencies of the exchange magnon and phonon temperatures. These results indicate that if--as is currently thought--the transverse spin Seebeck effect is caused by a temperature difference between the magnon and phonon baths, it must be the case that the magnon temperature is spectrally nonuniform and that the effect is driven by the sparsely populated dipolar region of the magnon spectrum.
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http://dx.doi.org/10.1103/PhysRevLett.111.107204 | DOI Listing |
Adv Mater
January 2025
Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
The chirality of magnons, exhibiting left- and right-handed polarizations analogous to the counterparts of spin-up and spin-down, has emerged as a promising paradigm for information processing. However, the potential of this paradigm is constrained by the controllable excitation and transmission of chiral magnons. Here, the magnon transmission is explored in the GdFeO/NiO/Pt structures.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
CAMD, Computational Atomic-Scale Materials Design, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
The magnetic properties of solids are typically analyzed in terms of Heisenberg models where the electronic structure is approximated by interacting localized spins. However, even in such models the evaluation of thermodynamic properties constitutes a major challenge and is usually handled by a mean field decoupling scheme. The random phase approximation (RPA) comprises a common approach and is often applied to evaluate critical temperatures although it is well known that the method is only accurate wellthe critical temperature.
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 PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, China. Electronic address:
Two-dimensional antiferromagnetic materials have attracted wide attention in both performance and application, which are of great significance for spin valves and next-generation magnetic random access memory devices. The spin-phonon coupling effect plays a crucial role in magnon dynamics. However, there is still a lack of research on the spin-phonon coupling effect of two-dimensional antiferromagnetic flakes.
View Article and Find Full Text PDFJ Phys Condens Matter
December 2024
Department of Physics, Indian Institute of Technology Delhi, IIT Delhi, Hauz Khas, New Delhi, Delhi, 110016, INDIA.
We have grown (111)- and (001)-oriented NiO thin films on (0001)-Sapphire and (001)-MgO substrates using pulsed laser deposition (PLD), respectively. DC magnetic susceptibility measurements underline that the Néel temperatures of the samples are beyond room-temperature. This is further confirmed by the presence of two-magnon Raman scattering modes in these films in ambient conditions.
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