Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Zhu, M.*; Romerio, V.*; Steiger, N.*; Nabi, S. D.*; 村井 直樹; 河村 聖子; Povarov, K. Y.*; Skourski, Y.*; Sibille, R.*; Keller, L.*; et al.
Physical Review Letters, 133(18), p.186704_1 - 186704_6, 2024/11
被引用回数：5 パーセンタイル：72.87(Physics, Multidisciplinary)Magnetic, thermodynamic, neutron diffraction and inelastic neutron scattering are used to study spin correlations in the easy-axis XXZ triangular lattice magnet K
Co(SeO
). Despite the presence of quasi-2D supersolid magnetic order, the low-energy excitation spectrum contains no sharp modes and is instead a broad and structured multiparticle continuum. Applying a weak magnetic field drives the system into an m = 1/3 fractional magnetization plateau phase and restores sharp spin wave modes. To some extent, the behavior at zero field can be understood in terms of spin wave decay. However, the presence of clear excitation minima at the M points of the Brillouin zone suggest that the spinon language may provide a more adequate description, and signals a possible proximity to a Dirac spin liquid state.
BWO
Nagl, J.*; Flavi
n, D.*; Hayashida, S.*; Povarov, K. Y.*; Yan, M.*; 村井 直樹; 河村 聖子; Simutis, F.*; Hicken, T. J.*; Luetkens, H.*; et al.
Physical Review Research (Internet), 6(2), p.023267_1 - 023267_18, 2024/06
We investigate the rare-earth-based frustrated quantum antiferromagnet PrBWO, previously considered a spin-liquid candidate. Our experimental and theoretical analysis reveals that its ground state is better described as a quantum paramagnet, governed by an Ising model in a transverse field. While in-plane correlations exist, the dominant interactions form frustrated triangular spin tubes via competing ferro-antiferromagnetic bonds. The system's thermodynamic and dynamic properties are significantly influenced by hyperfine interactions and weak structural disorder.
} polyoxo cluster UO
Cl
(MeO)
(x = 2.3, MeO = methoxide)Fichter, S.*; Radoske, T.*; 池田 篤史
Acta Crystallographica Section E; Crystallographic Communications (Internet), 77(8), p.847 - 852, 2021/08
A new type of polyoxo cluster complex that contains thirteen uranium atoms, {U}, was synthesised and characterised as [U(
-O
)(-O
)(-O)
Cl(O)
] (x = 2.3, MeO = methoxide) (I). The complex crystallises from methanol containing tetravalent uranium (U
) with a basic organic ligand. The characterised {U} polyoxo cluster complex possesses a single cubic uranium polyhedron at the centre of the cluster core. The observed shortening of U-O bonds, together with BVS calculations and the overall negative charge (2-) of (I), suggests that the central uranium atom in (I), that forms the single cubic polyhedron, is presumably oxidised to the pentavalent state (U
) from the original tetravalent state (U). Complex I is, hence, the first example of a polyoxo cluster possessing a single cubic coordination polyhedron of U.
(M=
Tc and Re) and MIDOA by ATR FT-IR and EXAFS spectroscopy and DFT calculation佐伯 盛久; 佐々木 祐二; Banerjee, D.*; Scheinost, A.*; Foerstendorf, H.*
no journal, ,
Structures of complexes of MO (M=Tc and Re) with MIDOA were investigated by IR and EXAFS spectroscopy. Analysis of observed spectra based on results of DFT calculation suggests that the complexes are stabilized by multiple hydrogen bonds.
- MIDOA錯体(M=Tc, Re)の構造研究佐伯 盛久; 佐々木 祐二; Banerjee, D.*; Scheinost, A.*; Foerstendorf, H.*
no journal, ,
近年、2,2'-(methylimino)bis(N,N-dioctyl-acetamide)(MIDOA)と呼ばれる有機抽出剤が開発され、この抽出剤により酸化物負イオンMOを効率的に水相から有機相へ抽出できることが明らかにされた。本研究ではその抽出メカニズムを解明するため、ATR FT-IR及びEXAFS分光法によりMO-MIDOA錯体のスペクトルを測定し、理論計算との比較により錯体構造を調べた。その結果、MIDOAは有機相中においてプロトン付加体H
MIDOAになり、MOはMIDOAと多点O...H-C水相結合により相互作用してMO...HMIDOAという錯体を形成することにより、大きく安定化していることが明らかになった。
佐藤 奈々; Schultheiss, K.*; K
rber, L.*; Puwenberg, N.*; M
hl, T.*; Awad, A. A.*; Arekapudi, S. S. P. K.*; Hellwig, O.*; Fassbender, J.*; Schultheiss, H.*
no journal, ,
In the last decade, two revolutionary concepts in nano magnetism emerged from research for advanced information processing and storage technologies. The first suggests the use of magnetic domain walls (DWs) in ferromagnetic nanowires to permanently store information in DW racetrack memories. The second proposes a hardware realisation of neuromorphic computing in nanomagnets using nonlinear magnetic oscillations in the GHz range. Both ideas originate from the transfer of angular momentum from conduction electrons to localised spins in ferromagnets, either to push data encoded in DWs along nanowires or to sustain magnetic oscillations in artificial neurones. Even though both concepts share a common ground, they live on very different time scales which rendered them incompatible so far. Here, we bridge both ideas by demonstrating the excitation of magnetic auto-oscillations inside nano-scale DWs using pure spin currents.
