Browsing by Author "Mitsuda, S"

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    Gapless spin liquid in a square-kagome lattice antiferromagnet
    (Springer Nature Limited, 2020-06-09) Fujihala, M; Morita, K; Mole, RA; Mitsuda, S; Tohyama, T; Yano, SI; Yu, DH; Sota, S; Kuwai, T; Koda, A; Okabe, H; Lee, H; Itoh, H; Hawai, T; Masuda, T; Sagayama, H; Matsuo, A; Kindo, K; Ohira-Kawamura, S; Nakajima, K
    Observation of a quantum spin liquid (QSL) state is one of the most important goals in condensed-matter physics, as well as the development of new spintronic devices that support next-generation industries. The QSL in two dimensional quantum spin systems is expected to be due to geometrical magnetic frustration, and thus a kagome-based lattice is the most probable playground for QSL. Here, we report the first experimental results of the QSL state on a square-kagome quantum antiferromagnet, KCu6AlBiO4(SO4)5Cl. Comprehensive experimental studies via magnetic susceptibility, magnetisation, heat capacity, muon spin relaxation (μSR), and inelastic neutron scattering (INS) measurements reveal the formation of a gapless QSL at very low temperatures close to the ground state. The QSL behavior cannot be explained fully by a frustrated Heisenberg model with nearest-neighbor exchange interactions, providing a theoretical challenge to unveil the nature of the QSL state. © 2020 Springer Nature Limited
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    Relief of spin frustration through magnetic anisotropy in the quasi-one-dimensional 𝑆= 1/2 antiferromagnet Na2⁢CuSO4⁢Cl2
    (American Physical Society (APS), 2022-03-29) Fujihala, M; Sakuma, Y; Mitsuda, S; Nakao, A; Munakata, K; Mole, RA; Yano, S; Yu, DH; Takehana, K; Imanaka, Y; Akaki, M; Okubo, S; Ohta, H
    We report the magnetic structure and anisotropy of the quasi-one-dimensional S=12 antiferromagnet Na2CuSO4Cl2 obtained by single-crystal neutron scattering, electron spin resonance (ESR), and magnetization measurements, following an earlier study of its dynamics [M. Fujihala, Phys. Rev. B 101, 024410 (2020)10.1103/PhysRevB.101.024410]. A Néel-Type spin structure is formed within the chain of this compound, where the spins point along the b axis, and ESR data indicate an antisymmetric exchange with a uniform Dzyaloshinskii-Moriya (DM) vector pointing along the b axis. The anisotropy g factor and magnetic structure are strong indicators of magnetic anisotropy originating from a symmetric anisotropic exchange interaction and/or a magnetic dipole interaction. These results suggest that these terms of the anisotropic spin Hamiltonian counteract the effect of the DM interaction and stabilize the Néel-Type structure in Na2CuSO4Cl2. ©2022 American Physical Society.