Pyrochlore systems are ideally suited to the exploration of geometrical frustration in three dimensions, and their rich phenomenology encompasses topological order and fractional excitations. Classical spin ices provide the first context in which it is possible to control emergent magnetic monopoles, and anisotropic exchange leads to even richer behaviour associated with large quantum fluctuations. Whether the magnetic ground state of YbTiO is a quantum spin liquid or a ferromagnetic phase induced by a Higgs transition appears to be sample dependent. Here we have determined the role of structural defects on the magnetic ground state via the diffuse scattering of neutrons. We find that oxygen vacancies stabilise the spin liquid phase and the stuffing of Ti sites by Yb suppresses it. Samples in which the oxygen vacancies have been eliminated by annealing in oxygen exhibit a transition to a ferromagnetic phase, and this is the true magnetic ground state.
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http://dx.doi.org/10.1038/s41467-019-08598-z | DOI Listing |
Chemphyschem
January 2025
Institute of Molecular Science Marseille, Département de chimie, FRANCE.
Electron delocalization is studied in the ground singlet and first excited triplet states of azulene-containing helicenes. After showing that the compounds we study can be synthesized, we show that they exhibit a charge separation in the ground state, which does not appear in their triplet excited state. Then, magnetically induced properties (IMS3D and ACID) and electron density decomposition methods (EDDB) are used to rationalize aromaticity in these systems.
View Article and Find Full Text PDFFunctional magnetic resonance imaging (fMRI) of the spinal cord is relevant for studying sensation, movement, and autonomic function. Preprocessing of spinal cord fMRI data involves segmentation of the spinal cord on gradient-echo echo planar imaging (EPI) images. Current automated segmentation methods do not work well on these data, due to the low spatial resolution, susceptibility artifacts causing distortions and signal drop-out, ghosting, and motion-related artifacts.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Philipps-Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Str. 4, 35032 Marburg, Germany.
Acenes are an important class of polycyclic aromatic hydrocarbons that have gained considerable attention from chemists, physicists, and material scientists, due to their exceptional potential for organic electronics. They serve as an ideal platform for studying the physical and chemical properties of sp carbon frameworks in the one-dimensional limit and also provide a fertile playground to explore magnetism in graphenic nanostructures due to their zigzag edge topology. While higher acenes up to tridecacene have been successfully generated by means of on-surface synthesis, it is imperative to extend their synthesis toward even longer homologues to comprehensively understand the evolution of their electronic ground state.
View Article and Find Full Text PDFInt J Numer Method Biomed Eng
January 2025
Dipartimento di Scienze Chirurgiche Odontostomatologiche e Materno-Infantili, Università di Verona, Verona, Italy.
Accurate reconstruction of the right heart geometry and motion from time-resolved medical images is crucial for diagnostic enhancement and computational analysis of cardiac blood dynamics. Commonly used segmentation and/or reconstruction techniques, exclusively relying on short-axis cine-MRI, lack precision in critical regions of the right heart, such as the ventricular base and the outflow tract, due to its unique morphology and motion. Furthermore, the reconstruction procedure is time-consuming and necessitates significant manual intervention for generating computational domains.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
College of Physics, Sichuan University, Chengdu, 610065, China.
Magnetic semiconductors with spin-polarized non-metallic atoms are usually overlooked in applications because of their poor performances in magnetic moments and under critical temperatures. Herein, magnetic characteristics of 2D pentagon-based XN (X = B, Al, and Ga) are revealed based on first-principles calculations. It was proven that XN structures are antiferromagnetic semiconductors with bandgaps of 2.
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