Gd2Te3: An antiferromagnetic semimetal
Journal
Journal of Physics Condensed Matter
Journal Volume
31
Journal Issue
28
Date Issued
2019
Author(s)
Muthuselvam I.P.
Abstract
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.
Subjects
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
Type
journal article