In this Letter, we devise a fast and effective nuclear spin hyperpolarization scheme, which is, in principle, magnetic field independent. We use this scheme to experimentally demonstrate polarizations of up to 66% for phosphorus donor nuclear spins in bulk silicon, which are created within less than 100 μs in a magnetic field of 0.35 T at a temperature of 5 K. The polarization scheme is based on a spin-dependent recombination process via weakly coupled spin pairs, for which the recombination time constant strongly depends on the relative orientation of the two spins. We further use this scheme to measure the nuclear spin relaxation time and find a value of ∼100 ms under illumination, in good agreement with the value calculated for nuclear spin flips induced by repeated ionization and deionization processes.
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http://dx.doi.org/10.1103/PhysRevLett.114.117602 | DOI Listing |
J Am Chem Soc
January 2025
Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
High-performance and cost-effective hole-collecting materials (HCMs) are indispensable for commercially viable perovskite solar cells (PSCs). Here, we report an anchorable HCM composed of a triazatruxene core connected with three alkyl carboxylic acid groups (). In contrast to the phosphonic acid-containing tripodal analog (), molecules can form a hydrophilic monolayer on a transparent conducting oxide surface, which is beneficial for subsequent perovskite film deposition in the traditional layer-by-layer fabrication process.
View Article and Find Full Text PDFACS Nano
January 2025
School of Physical Sciences, National Institute of Science Education and Research, HBNI, Jatni 752050, India.
Topological magnetic skyrmions with helicity state degrees of freedom in centrosymmetric magnets possess great potential for advanced spintronics applications and quantum computing. Till date, the skyrmion study in this class of materials mostly remains focused to collinear ferromagnets with uniaxial magnetic anisotropy. Here, we present a combined theoretical and experimental study on the competing magnetic exchange-induced evolution of noncollinear magnetic ground states and its impact on the skyrmion formation in a series of centrosymmetric hexagonal noncollinear magnets, MnFeCoGe.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel.
The sensitivity of solid state nuclear magnetic resonance spectroscopy can be enhanced via dynamic nuclear polarization (DNP) using unpaired electrons as polarizing agents. In metal ions based (MI)-DNP, paramagnetic metal ions are introduced as dopants into inorganic materials serving as endogenous polarizing agents. Having polarizing agents as part of the structure enables signal enhancements within the bulk of the material.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Physics, University of Northeastern, IMIT-CONICET, Av. Libertad, 5500 Corrientes, Argentina.
In this study, we worked at the CCSD/aug-cc-pVTZ level to obtain the conformers of glycine in its neutral and zwitterionic forms in the gas and water phases. We then computed the NMR properties (spin-spin coupling constants and nuclear magnetic shieldings) at the SOPPA/aug-cc-pVTZ-J level. We attempt to elucidate the apparent discrepancy arising from two previous works by Valverde et al.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha No 10, Bandung 40132, Jawa Barat, Indonesia.
The magnetic, electronic, and topological properties of GdPtBi were systematically investigated using first-principles density functional theory (DFT) calculations. Various magnetic configurations were examined, including ferromagnetic (FM) and antiferromagnetic (AFM) states, with particular focus on AFM states where the Gd magnetic moments align either parallel (AFM) or perpendicular (AFM) to the [111] crystal direction. For AFM, the in-plane angles were varied at = 0°, 15°, and 30° (denoted as AFM, AFM, and AFM, respectively).
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