Browsing by Author "Gitgeatpong, G"

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    Erratum: Magnetic structure and dzyaloshinskii-moriya interaction in the S=1/2 helical-honeycomb antiferromagnet α−Cu2V2O7 [Phys. Rev. B 92, 024423 (2015)]
    (American Physical Society, 2017-03-10) Gitgeatpong, G; Zhao, Y; Avdeev, M; Piltz, RO; Sato, TJ; Matan, K
    No abstract available. See the original item at: https://apo.ansto.gov.au/dspace/handle/10238/10250
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    Magnetic properties and magnetic structure of the frustrated quasi-one-dimensional antiferromagnet SrCuTe2O6
    (American Physical Society, 2020-10-07) Saeaun, P; Zhao, Y; Piyawongwatthana, P; Sato, TJ; Chou, FC; Avdeev, M; Gitgeatpong, G; Matan, K
    Magnetization measurements on single-crystal cubic SrCuTe2O6 with an applied magnetic field along three inequivalent high symmetry directions [100], [110], and [111] reveal weak magnetic anisotropy. The fits of the magnetic susceptibility to the result from a quantum Monte Carlo simulation on the Heisenberg spin-chain model, where the chain is formed via the dominant third-nearest-neighbor exchange interaction J3, yield the intrachain interaction (J3/kB) between 50.12(7) K for the applied field along [110] and 52.5(2) K along [100] with about the same g factor of 2.2. Single-crystal neutron diffraction unveils the transition to the magnetic ordered state as evidenced by the onset of the magnetic Bragg intensity at TN1=5.25(9)K with no anomaly of the second transition at TN2 reported previously. Based on irreducible representation theory and magnetic space group analysis of powder and single-crystal neutron diffraction data, the magnetic structure in the Shubnikov space group P4132, where the Cu2+S=1/2 spins antiferromagnetically align in the direction perpendicular to the spin chain, is proposed. The measured ordered moment of 0.52(6)μB, which represents 48% reduction from the expected value of 1μB, suggests the remaining influence of frustration resulting from the J1 and J2 bonds. ©2020 American Physical Society
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    Magnetic properties of the S = 1/2 antiferromagnetic spin-chain α - Cu2V2O7
    (American Physical Society, 2015-03-06) Gitgeatpong, G; Zhao, Y; Avdeev, M; Piltz, RO; Sato, TJ; Matan, K
    Magnetic properties of the S = 1 / 2 antiferromagnetic spin-chain, α - Cu2V2O7, have been studied using magnetization and neutron scattering measurements on powder and single-crystal samples. Magnetic susceptibility reveals a Curie-Weiss temperature of Θ = -73.2(9) K with a magnetic phase transition at TN = 33 K while the Bonner-Fisher fit to the magnetic susceptibility for T >TN with magnetic field perpendicular to the crystallographic a - axis yields the intra-chain coupling of |J|/k = 46.0(2) K. Small ferromagnetism below TN is due to spin-canting caused by Dzyaloshinskii-Moriya interactions. Analysis of the neutron diffraction data reveals that the Cu2+ spins are coupled antiferromagnetically along zigzag chains, which run alternately along [011] and [01-1] directions. The ordered moment of 0.925(3) μB is predominantly along the a - axis. Our recent inelastic neutron scattering, which reveals atypical magnetic excitations centered at commensurate wave vectors (0, +/-0.25, 0) around the magnetic zone center, will also be discussed. © 2021 American Physical Society
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    Magnetic structure and dzyaloshinskii-moriya interaction in the S=12 helical-honeycomb antiferromagnet α−Cu2V2O7
    (American Physical Society, 2015-07-23) Gitgeatpong, G; Zhao, Y; Avdeev, M; Piltz, RO; Sato, TJ; Matan, K
    Magnetic properties of the S=12 antiferromagnet α−Cu2V2O7 have been studied using magnetization, quantum Monte Carlo (QMC) simulations, and neutron diffraction. Magnetic susceptibility shows a broad peak at ∼50K followed by an abrupt increase indicative of a phase transition to a magnetically ordered state at TN=33.4(1) K. Above TN, a fit to the Curie-Weiss law gives a Curie-Weiss temperature of Θ=−73(1) K suggesting the dominant antiferromagnetic coupling. The result of the QMC calculations on the helical-honeycomb spin network with two antiferromagnetic exchange interactions J1 and J2 provides a better fit to the susceptibility than the previously proposed spin-chain model. Two sets of the coupling parameters J1:J2=1:0.45 with J1=5.79(1) meV and 0.65:1 with J2=6.31(1) meV yield equally good fits down to ∼TN. Below TN, weak ferromagnetism due to spin canting is observed. The canting is caused by the Dzyaloshinskii-Moriya interaction with an estimated bc-plane component |Dp|≃0.14J1. Neutron diffraction reveals that the S=12Cu2+ spins antiferromagnetically align in the Fd′d′2 magnetic space group. The ordered moment of 0.93(9) μB is predominantly along the crystallographic a axis. ©2015 American Physical Society