Polar vortices are predominantly observed within the confined ferroelectric films and the ferroelectric/paraelectric superlattices. This raises the intriguing question of whether polar vortices can form within relaxor ferroelectric ceramics and subsequently contribute to their energy storage performances. Here, we incorporate 10 mol % CaSnO into the 0.7NaNbO-0.3SrBiTiO matrix, yielding a coexistence of phases: 48.8% orthorhombic 2/, 49.1% tetragonal 4, and 2.1% tetragonal 4/ SnO, which is confirmed by the combination of X-ray diffraction and transmission electron microscopy. The ceramic features a pronounced core-shell structure with the shell region rich in stripe nanoscale domains of the 2/ phase and the core region consisting of polar nanoregions deficient in the 2/ phase, forming polar vortices. Consequently, the ceramic achieves an impressive recoverable energy storage density of 6.83 J cm and an exceptional efficiency of 95.7% at a high breakdown strength of 750 kV cm, along with superior stability in frequency, temperature, and cycling. These results not only offer a viable approach for developing high-performance energy storage ceramics through the controlled formation of polar vortices but also offer the potential for direct electric-field control of polar vortices for high-speed data processing and storage.
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http://dx.doi.org/10.1021/acsnano.4c16672 | DOI Listing |
ACS Nano
January 2025
Functional Materials Research Laboratory, School of Materials Science and Engineering, Tongji University, Shanghai 201804, P. R. China.
Polar vortices are predominantly observed within the confined ferroelectric films and the ferroelectric/paraelectric superlattices. This raises the intriguing question of whether polar vortices can form within relaxor ferroelectric ceramics and subsequently contribute to their energy storage performances. Here, we incorporate 10 mol % CaSnO into the 0.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China.
We show that spontaneous density segregation in dense systems of aligning circle swimmers is a condensation phenomenon at odds with the phase separation scenarios usually observed in two-dimensional active matter. The condensates, which take the form of vortices or rotating polar packets, can absorb a finite fraction of the particles in the system, and keep a finite or slowly growing size as their mass increases. Our results are obtained both at particle and continuous levels.
View Article and Find Full Text PDFSci Rep
January 2025
School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China.
Recently, vortex beams have been widely studied and applied because they carry orbital angular momentum (OAM). It is widely acknowledged in the scientific community that fractional OAM does not typically exhibit stable propagation; notably, the notion of achieving stable propagation with dual-fractional OAM within a single optical vortex has been deemed impracticable. Here, we address the scientific problem through the combined modulation of phase and polarization, resulting in the generation of a dual-fractional OAM vector vortex beam that can stably exist in free space.
View Article and Find Full Text PDFNat Commun
December 2024
School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
Polar topologies, such as vortex and skyrmion, have attracted significant interest due to their unique physical properties and promising applications in high-density memory devices. To date, all known polar vortices are present in or induced by ferroelectric materials. In this study, we find polar vortex arrays in paraelectric SrTiO.
View Article and Find Full Text PDFSci Adv
December 2024
Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China.
Optical spin and orbital angular momenta are intrinsic characteristics of light determined by its polarization and spatial degrees of freedom, respectively. At the nanoscale, sharply focused structured light carries coupled spin-orbital angular momenta with complex 3D nearfield structures, crucial for manipulating multidimensional information of light in nanophotonics. However, characterizing these interactions faces challenges with conventional farfield-based methods, which typically lack the essential accuracy and resolution to interrogate the structured nearfield with high fidelity.
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