Browsing by Author "Kolodiazhnyi, T"

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    Giant magnetocapacitance in cerium sesquioxide
    (American Physical Society, 2018-08-22) Kolodiazhnyi, T; Sakurai, H; Avdeev, M; Charoonsuk, T; Lamonova, KV; Pashkevich, YG; Kennedy, BJ
    We report structural, magnetic, magnetodielectric, and specific heat properties of hexagonal polymorph of Ce2O3. The A-type hexagonal Ce2O3 crystallizes in the P¯32/m1 space group and shows antiferromagnetic ordering at TN≈6.2 K as detected by magnetic susceptibility measurements. The magnetic ordering is accompanied by a λ-shape specific heat anomaly with a peak maximum at T≈6.1 K. An isotropic dielectric constant demonstrates a large magnetocapacitance effect at T=TN, which saturates at ∼80 kOe. In the magnetically ordered phase the relaxation rate of the dielectric polarization increases with the magnetic field and shows divergence as the temperature approaches TN. The magnetic calculations indicate that Ce 2O3 undergoes “easy plane” AFM ordering, which is also supported by the neutron diffraction data. ©2018 American Physical Society
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    Neutron powder diffraction study of the magnetic structure of EuZrO3
    (IOP Science, 2014-02-13) Avdeev, M; Kennedy, BJ; Kolodiazhnyi, T
    Neutron powder diffraction experiments on the orthorhombic perovskite EuZrO3 show it to have an antiferromagnetic G-type magnetic structure with the magnetic moments aligned parallel to the a-axis. The orthorhombic crystal structure is a consequence of cooperative rotations of the corner-sharing ZrO6 octahedra. The crystal structure does not change significantly below the Néel temperature, ~4.1 K, showing there to be only weak magnetoelastic coupling. © 2014, IOP Publishing Ltd.
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    Studies of the antiferrodistortive transition in EuTiO3
    (Institute of Physics, 2014-11-12) Kennedy, BJ; Murphy, GL; Reynolds, EM; Avdeev, M; Brand, HEA; Kolodiazhnyi, T
    Structural studies of EuTiO3, conducted using synchrotron x-ray powder diffraction, reveal the sensitivity of this material to defects. The presence of a single tetragonal–cubic (I4/mcm–Pm-3m) transition is confirmed. Neutron diffraction measurements show EuTiO3 to have a G-type antiferromagnetic arrangement. Examinations of the symmetry-adapted tetragonal strains demonstrate that the stoichiometry impacts on the continuous nature of this. The impact of defects on the electrical conductivity and magnetodielectric effect is also described. © 2014 IOP Publishing Ltd