Browsing by Author "Manaka, H"
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- ItemMagnetic order in the chemically substituted frustrated antiferromagnet CsCrF 4(American Physical Society, 2020-11-24) Hayashida, S; Hagihala, M; Avdeev, M; Miura, Y; Manaka, H; Masuda, TThe effect of chemical substitution on the ground state of the geometrically frustrated antiferromagnet CsCrF4 has been investigated through a neutron powder diffraction experiment. Magnetic Fe-substituted CsCr0.94Fe0.06F4 and nonmagnetic Al-substituted CsCr0.98Al0.02F4 samples are measured, and magnetic Bragg peaks are clearly observed in both samples. Magnetic structure analysis revealed a 120∘ structure having a magnetic propagation vector kmag=(0,0,1/2) in CsCr0.94Fe0.06F4. For CsCr0.98Al0.02F4, a quasi- 120∘ structure having kmag=(1/2,0,1/2) is formed. It is notable that the identified magnetic structure in CsCr 0.94Fe0.06F4 belongs to a different phase of ground states from those in CsCr0.98Al0.02F4 and the parent CsCrF4. These results suggest that the Fe substitution strongly influences the ground state of CsCrF4.©2020 American Physical Society
- ItemMagnetic states of coupled spin tubes with frustrated geometry in CsCrF 4(Nature Publishing Group, 2019-04-23) Hagihala, M; Hayashida, S; Avdeev, M; Manaka, H; Kikuchi, H; Masuda, TWhen a theoretical model is realized in nature, small perturbation terms play important roles in the selection of the ground state in geometrically frustrated magnets. In case of a triangular spin tube, the two-dimensional network of the inter-tube interaction forms characteristic lattices. Among them Kagome-Triangular (KT) lattice is known to exhibit an enriched phase diagram including various types of non-trivial structures: non-coplanar cuboc structure, coplanar 120° structure with the two-dimensional propagation vector of k2D = (0, 0), 3–√×3–√ structure with k2D = (1/3, 1/3), and incommensurate structure. We investigate the magnetic state in the model material CsCrF4 by using neutron diffraction technique. Combination of representation analysis and Rietveld refinement reveals that a very rare structure, i.e., a quasi-120° structure with k2D = (1/2, 0), is realized at the base temperature. The classical calculation of the phase diagram elucidates that CsCrF4 is the first experimental realization of the KT lattice having ferromagnetic Kagome bond. A single-ion anisotropy and Dzyaloshinskii-Moriya interaction play key roles in the selection of the ground state. Furthermore, a successive phase transition having an intermediate state represented by k2D = (1/3, 1/3) is observed. The intermediate state is a partially ordered 120° structure which is induced by thermal fluctuation. © 2019, The Author(s)
- ItemNeutron scattering study of magnetic structure in triangle spin tube CsCrF4(American Physical Society, 2016-03) Hagihala, M; Avdeev, M; Manaka, H; Masuda, TTriangle spin tube viewed from tube direction is topologically equivalent to kagomé lattice. The rung (J1) and inter-tube (J2) interactions on triangle spin tube correspond respectively to the next nearest neighbor and the nearest neighbor interactions on kagomé lattice. In the case of J1>0 (Antiferromagnetic) and J1>>|J2|, the ground state is q=0,120∘ structure with J2>0 or Cuboc state that represented multi-q (q=2π(1/2 0) and two symmetric-equivalent vectors) with J2<0 [1]. CsCrF4 is a perfect triangle spin tube material with antiferromagnetic intra-tube and rung interactions [2]. Neutron diffraction measurement revealed magnetic long-range order at T=1.5 K. Contrary to the expectation, the magnetic structure was determined q=2π(1/2 0 1/2), 120∘ structure by Rietveld refinement. We also confirmed that this structure was stabilized by Dzyaloshinskii -Moriya interaction and small anisotropy that obeyed the three-fold symmetry at Cr sites by calculation. © 2021 American Physical Society