We report a giant hysteretic spin Seebeck effect (SSE) anomaly with a sign reversal at magnetic fields much stronger than the coercive field in a (001)-oriented Tb_{3}Fe_{5}O_{12} film. The high-field SSE enhancement reaches 4200% at approximately 105 K over its weak-field value and presents a nonmonotonic dependence on temperature. The unexpected high-field hysteresis of SSE is found to be associated with a magnetic transition of double-umbrella spin texture in TbIG. Nearly parallel dispersion curves of magnons and acoustic phonons around this neoteric transition are supported by theoretical calculations, leading to a high density of field-tuned magnon polarons and consequently an extraordinarily large SSE. Our study provides insight into the evolution of magnon dispersions of double-umbrella TbIG and could potentially boost the efficiency of magnon-polarons SSE devices.
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http://dx.doi.org/10.1103/PhysRevLett.132.056702 | DOI Listing |
Phys Chem Chem Phys
January 2025
Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
An modelling workflow is used to predict the thermoelectric properties and figure of merit of the lanthanide cobalates LaCoO, PrCoO and NdCoO in the orthorhombic phase with the low-spin magnetic configuration. The LnCoO show significantly lower lattice thermal conductivity than the widely-studied SrTiO, due to lower phonon velocities, with a large component of the heat transport through an intraband tunnelling mechanism characteristic of amorphous materials. Comparison of the calculations to experimental measurements suggests the p-type electrical properties are significantly degraded by the thermal spin crossover, and materials-engineering strategies to suppress this could yield improved .
View Article and Find Full Text PDFAdv 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 PDFSci Adv
January 2025
Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001, USA.
Superconducting spintronics explores the interplay between superconductivity and magnetism, sparking substantial interest in nonunitary superconductors as a platform for magneto-superconducting phenomena. However, identifying nonunitary superconductors remains challenging. We demonstrate that spin current driven by thermal gradients sensitively probes the nature of the condensate in nonunitary superconductors.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Yutian Road 500, Shanghai, 200083, China.
Phys Chem Chem Phys
December 2024
College of Science, Nanjing University of Posts and Telecommunications, Nanjing 210046, China.
Inspired by the recently reported novel two-dimensional material BCP, we performed one-dimensional shearing along the zigzag direction to obtain four BCP nanoribbons with various edge atom combinations. An asymmetric hydrogen passivation scheme was employed to modulate the electronic properties and successfully open the band gap, especially the 2H-1H passivation with dihydrogenation and monohydrogenation at the top and bottom edges, respectively, achieving bipolar magnetic semiconductors with edge P-atoms contributing to the main magnetism. Furthermore, three crucial spin-polarized transmission spectra yielded a significant spin-dependent Seebeck effect (SDSE), displaying superior thermoelectric conversion capabilities by generating pure spin currents.
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