https://scholars.lib.ntu.edu.tw/handle/123456789/573439
標題: | Gd2Te3: An antiferromagnetic semimetal | 作者: | Muthuselvam I.P. GUANG-YU GUO et al. |
關鍵字: | Antiferromagnetism; Calculations; Density functional theory; Ground state; Magnetic moments; Magnetic susceptibility; Magnetization; Single crystals; Specific heat of solids; Tellurium compounds; Antiferromagnetsm; Curie-Weiss temperature; Easy direction of magnetizations; Electronic band structure; Electronic specific heat; Field-induced transitions; Ordered magnetic moments; Superexchange interaction; Gadolinium compounds | 公開日期: | 2019 | 卷: | 31 | 期: | 28 | 來源出版物: | Journal of Physics Condensed Matter | 摘要: | We report high-precision magnetization (M(T,H)), magnetic susceptibility (χ(T,H)), specific heat (Cp (T, H)) and 'zero-field' electrical resistivity, ρ(T,H = 0), data taken on Gd2Te3 single crystal over wide ranges of temperature and magnetic field (H), with either H b-axis or H ac-plane. M(T,H) and χ(T,H) unambiguously establish that the b-axis is the easy direction of magnetization whereas any direction in the ac-plane is a hard direction. The -type anomaly in 'zero-field' specific heat, Cp (T, H = 0), and an abrupt drop in ρ(T,H = 0) (characteristic of the paramagnetic (PM) - antiferromagnetic (AFM) phase transition) are observed at the N?el temperature, TN = 15.3(1) K. χ(T,H) and Cp(T,H) clearly demonstrate that TN shifts to lower temperatures with increasing H irrespective of whether H points in the easy or hard direction. When H b, the M(H) isotherms at temperatures in the range 2.5 K ? T ? 10 K reveal the existence of a field-induced spin-flop (SF) transition at fields 4.0 T ? HSF ? 4.5 T. The first principles electronic band structure and density of states calculations, based on the density functional theory, correctly predict an AFM ground state (stabilized primarily by the 4f Gd3+ - 5p Te2- - 4f Gd3+ superexchange interactions) and the observed semi-metallic behavior for the Gd2Te3 compound. Moreover, these calculations yield the values μGd = 7.1 μB for the ordered magnetic moment per Gd atom at T = 0, γ = 0.14 mJ mol-1 K-2 for the Sommerfeld coefficient for the electronic specific heat contribution and θCW = -3.32 K for the Curie-Weiss temperature, respectively. These theoretical estimates conform well with the corresponding experimental values μGd = 7.0 μB, γ = 0.18(3) mJ mol-1 K-2 and θCW = -3.6 K. ? 2019 IOP Publishing Ltd Printed in the UK. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065810940&doi=10.1088%2f1361-648X%2fab1570&partnerID=40&md5=1c74a6774dd8e7e07337beb80cb12823 https://scholars.lib.ntu.edu.tw/handle/123456789/573439 |
ISSN: | 9538984 | DOI: | 10.1088/1361-648X/ab1570 |
顯示於: | 物理學系 |
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