One-ninth magnetization plateau stabilized by spin entanglement in a kagome antiferromagnet

The spin-1/2 antiferromagnetic Heisenberg model on a Kagome lattice is geometrically frustrated, which is expected to promote the formation of many-body quantum entangled states. The most sought-after among these is the quantum spin liquid phase, but magnetic analogs of liquid, solid, and supersolid phases may also occur, producing fractional plateaus in the magnetization. Here, we investigate the experimental realization of these predicted phases in the Kagome material YCu3(OD)6+xBr3-x (x=0.5). By combining thermodynamic and Raman spectroscopic techniques, we provide evidence for fractionalized spinon excitations and observe the emergence of a 1/9 magnetization plateau. These observations establish YCu3(OD)6+xBr3-x as a model material for exploring the 1/9 plateau phase.Comment: to appear in Nature Physics, 33 pagses, 15 figure

Simulation-based planning system for shipbuilding

To maintain the competitiveness of shipyards in the current, difficult situation, further improvements to technology are necessary. Recently, various production technologies have been developed to advance the shipyard production environment under the influence of the Industry 4.0 toward automation, smart factories, and intelligent planning systems. To contribute to such efforts, we introduce a research case aimed at a simulation-based shipbuilding planning system. Shipbuilding planning processes are reorganized using an integrated planning and scheduling system, and a process-centric discrete event system simulation is used to enhance planning quality. Moreover, the proposed simulation-based planning system is applied to an actual shipbuilding process, proving that it could enhance the quality of production planning through several productivity evaluation indices.Y

Spin dynamics of the one-dimensional double chain spin- 12 antiferromagnet KNaCuP2 O7

© 2022 American Physical Society.We combine a muon spin relaxation (μSR) technique with thermodynamic measurements to explore the spin dynamics of one-dimensional (1D) S=12 antiferromagnetic double chain KNaCuP2O7. Static magnetic susceptibility and specific heat are well described by a uniform 1D spin chain model with the intrachain interaction J/kB≈55K and small interchain interactions. Spin excitations probed by zero-field μSR evince that high-temperature diffusive spin transport turns into ballistic behavior with decreasing temperature below 30 K. In addition, we observe that longitudinal-field μSR varies hardly with an external magnetic field. The field-independent dynamical spin susceptibility disagrees with diffusive or ballistic behaviors.11Nsciescopu

Li₆M(SeO₃)₄ (M = Co, Ni, and Cd) and Li₂Zn(SeO₃)₂: Selenites with Late Transition-Metal Cations

A series of lithium metal selenites, Li₆M­(SeO₃)₄ (M = Co, Ni, and Cd) and Li₂Zn­(SeO₃)₂, were synthesized by hydrothermal and solid-state reactions. Li₆M­(SeO₃)₄ is composed of Li⁺ cations, MO₆ octahedra, and SeO₃ polyhedra, while Li₂Zn­(SeO₃)₂ consists of Li⁺, Zn­(Li)­O₄ tetrahedra, and SeO₃ polyhedra. Isostructural Li₆Co­(SeO₃)₄ and Li₆Ni­(SeO₃)₄ crystallize in the rhombohedral space group <i>R</i>3̅, forming a three-dimensional distorted cubic lattice. Li₂Zn­(SeO₃)₂ crystallizes in the orthorhombic space group <i>Pbam</i> and reveals a layered structure in the <i>bc</i> plane. Li₆Cd­(SeO₃)₄ revealing a unidimensional structure crystallizes in the polar non-centrosymmetric space group <i>C</i>2, attributed to the parallel alignment of distorted CdO₆ octahedra. The direct-current magnetic susceptibility measurements unveil that Li₆Co­(SeO₃)₄ is a canted antiferromagnet with <i>T</i>_N = 25 K, while Li₆Ni­(SeO₃)₄ undergoes an antiferromagnetic transition at <i>T</i>_N = 54 K, having a negligible canted moment. The weak ferromagnetism observed in Li₆Co­(SeO₃)₄ indicates the significance of spin–orbit coupling, bringing about anisotropic exchange interactions. Li₆Cd­(SeO₃)₄ reveals a second harmonic generation (SHG) efficiency of 10 × α-SiO₂. Dipole moment calculations on Li₆Cd­(SeO₃)₄ indicate that the cooperative interaction of CdO₆ and SeO₃ is responsible for the observed SHG properties. Band gaps of the compounds are enlarged as atomic number increases. The effect of late transition-metal cations with different coordination numbers on the framework structures and the subsequent physical properties will be also discussed

Coexistence of random singlets and disordered Kitaev spin liquid in H3LiIr2O6

©2023 American Physical Society. We combine static magnetic susceptibility chi(T), muon-spin relaxation, and H-1 nuclear magnetic resonance measurements to explore the spin dynamics in the disordered-induced quantum spin liquid candidate H3LiIr2O6. Inverse Laplace transform analysis of the H-1 spin-lattice relaxation rate 1/T-1 enables us to identify two characteristic temperatures Tg = 110 K and T* = 26 K. Below T-g, a slower 1/T-1(slow) component dictated by gapped excitations with a spin gap Delta(h) = 30-38 K evolves distinctly from a faster 1/T-1(fast) component pertaining to gapless excitations. Furthermore, we observe a sub-Curie divergent chi(T) proportional to T-0.68, a power-law dependent 1/T fast 1 proportional to T 1.4, and a weakly activated 1/(slow)(T) 1 proportional to exp(-Delta(l)/k(B)T) (Delta(l) = 3-6 K) below T* = 26 K. All these features suggest the coexistence of a disordered spin-liquid state and spin singlets with spatially distributed gaps.11Nsciescopu

Timescale distributions of spin fluctuations in the S=2 kagome antiferromagnet CsMn3 F6 (SeO3)2

© 2022 American Physical Society.We report the static and dynamical properties of a newly discovered S=2 kagome antiferromagnet CsMn3F6(SeO3)2. By combining dc and ac magnetic susceptibilities, specific heat, electron spin resonance (ESR), and muon spin relaxation (μSR), we identify two characteristic temperatures T∗=8 K and T=|ΘCW|=49(1) K, thereby three distinct regimes: a paramagnetic, a cooperative paramagnetic, and a quasistatic ordered state. At high temperature (T>|ΘCW|), the ac susceptibility and ESR linewidth show a power-law dependence, reflecting short-range spin-spin correlations of the paramagnetic Mn3+ ions. In the cooperative paramagnetic regime (T∗<T<|ΘCW|), the ESR signals evince the development of dichotomic spin correlations, which is interpreted in terms of the distinct timescales of in-plane and out-of-plane spin fluctuations. Remarkably, we observe a broad maximum at the characteristic temperature scale of Tcl=20 K (≈|Jcl|) in the specific heat and ESR results, suggesting short-range ordering. At low temperatures below T∗, the μSR data suggest the presence of dynamically fluctuating fields with partially frozen moments, consistent with the absence of long-range order evidenced by specific heat and magnetic susceptibility data. A magnetic behavior that depends on the chosen time window points to the presence of multiple timescales and temporally anisotropic spin correlations, as predicted for a classical kagome antiferromagnet.11Nsciescopu

Open-Framework Iron Fluoride Phosphates Based on Chain, Trinuclear, and Tetranuclear Chain FeIIIBuilding Units: Crystal Structures and Magnetic Properties

Copyright © 2022 American Chemical Society. We report the synthesis and characterization of a series of new open-framework iron fluoride-fluorophosphates based on linear, trinuclear, and tetranuclear chain FeIII building units. KFe2(PO3F)2F3 (I) consists of {Fe2(O3F)2F2}10- zigzag chains interconnected by P(O/F)4 tetrahedra forming a three-dimensional (3D) open framework. K2Fe(PO2.5F1.5)2F2 (II) is built up by {Fe(PO2.5F1.5)2F2}2- chains separated by K+ cation layers. The framework for K3Fe3(PO4)(PO3F)2F5 (III) contains two-dimensional {Fe3O4F4(PO3F)2}2- sheets, which are built from trimeric Fe-octahedra insulated by PO3F tetrahedra. The macroanionic framework of K3Fe4(PO4)2F9 (IV) comprises linear {Fe4O8F9}10- chains consisting of tetranuclear magnetic clusters of [Fe4O8F9]10- formed via corner-sharing fluorine atoms decorated with PO4 groups. The magnetic characterization of three iron fluorophosphates reveals diversified magnetism: S = 5/2 spin chains for I, antiferromagnetically coupled triangular Fe units for III, and coupled tetrahedral S = 5/2 spin chains for IV. IV shows strong geometric frustration thanks to its spin motifs of corner-shared tetrahedral clusters. © 2022 American Chemical Society.11Nsciescopu

Synthesis and Characterization of Three New Layered Vanadium Tellurites, MVTe₂O₈ (M = Al, Ga, and Mn): Three-Dimensional (3-D) Antiferromagnetic Behavior of MnVTe₂O₈ with a Zigzag <i>S</i> = 2 Spin Chain

Three new metal vanadium tellurites, MVTe₂O₈ (M = Al, Ga, and Mn) have been synthesized through standard solid-state and hydrothermal reactions. Crystal structure analyses using X-ray diffraction reveal that the isostructural materials exhibit layered structures consisting of MO₆, TeO₄, and VO₄ polyhedra. The corner-sharing of MO₆ octahedra results in one-dimensional (1-D) zigzag chains that are further interconnected by tetrameric Te₄O₁₂ units and the VO₄ tetrahedra to complete a layered structure. Detailed structural analysis suggests that the unit-cell volumes and the very long Te(2)–O(2) bond distances in MVTe₂O₈ are closely related to the ionic radii of M³⁺ cations. Additional characterizations such as ultraviolet–visible light (UV-vis) and infrared spectroscopies, thermogravimetric analyses, and electron paramagnetic resonance measurements were performed. The temperature-dependent magnetic susceptibility measurements on MnVTe₂O₈ suggest that the material behaves like a three-dimensional (3-D) antiferromagnet with <i>T</i>_<i>N</i> = 30 K, although the structure consists of a zigzag <i>S</i> = 2 spin chain

Synthesis and Characterization of Three New Layered Vanadium Tellurites, MVTe₂O₈ (M = Al, Ga, and Mn): Three-Dimensional (3-D) Antiferromagnetic Behavior of MnVTe₂O₈ with a Zigzag <i>S</i> = 2 Spin Chain

Three new metal vanadium tellurites, MVTe₂O₈ (M = Al, Ga, and Mn) have been synthesized through standard solid-state and hydrothermal reactions. Crystal structure analyses using X-ray diffraction reveal that the isostructural materials exhibit layered structures consisting of MO₆, TeO₄, and VO₄ polyhedra. The corner-sharing of MO₆ octahedra results in one-dimensional (1-D) zigzag chains that are further interconnected by tetrameric Te₄O₁₂ units and the VO₄ tetrahedra to complete a layered structure. Detailed structural analysis suggests that the unit-cell volumes and the very long Te(2)–O(2) bond distances in MVTe₂O₈ are closely related to the ionic radii of M³⁺ cations. Additional characterizations such as ultraviolet–visible light (UV-vis) and infrared spectroscopies, thermogravimetric analyses, and electron paramagnetic resonance measurements were performed. The temperature-dependent magnetic susceptibility measurements on MnVTe₂O₈ suggest that the material behaves like a three-dimensional (3-D) antiferromagnet with <i>T</i>_<i>N</i> = 30 K, although the structure consists of a zigzag <i>S</i> = 2 spin chain

Noncollinear magnetic order, in-plane anisotropy, and magnetoelectric coupling in the pyroelectric honeycomb antiferromagnet Ni2Mo3 O8

©2023 American Physical Society. Ni2Mo3O8 is a pyroelectric honeycomb antiferromagnet exhibiting peculiar changes in its electric polarization at magnetic transitions. Ni2Mo3O8 stands out from isostructural magnetic compounds, showing an anomalously low magnetic transition temperature and unique magnetic anisotropy. We determine the magnetic structure of Ni2Mo3O8 utilizing high-resolution powder and single-crystal neutron diffraction. A noncollinear stripy antiferromagnetic order is found in the honeycomb planes. The magnetic space group is PCna21. The in-plane magnetic connection is of the stripy type for both the ab-plane and c-axis spin components. This is a simpler connection than the one proposed previously. The ferromagnetic interlayer order of the c-axis spin components in our model is also distinct. The magnetic anisotropy of Ni2Mo3O8 is characterized by orientation-dependent magnetic susceptibility measurements on a single crystal, consistent with neutron diffraction analysis. The local magnetoelectric tensor analysis using our magnetic models provides insights into its magnetoelectric coupling and polarization. Thus, our results deliver essential information for understanding both the unusual magnetoelectric properties of Ni2Mo3O8 and the prospects for observing exotic nonreciprocal, Hall, and magnonic effects characteristic of this compound family. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article&apos;s title, journal citation, and DOI.11Nscopu