Abstract
By developing models of increasing complexity, we show that a model without single-ion anisotropy (SIA) cannot explain the magnetic properties of Jeff=1/2 Tb3+ moments in the orthorhombically distorted, honeycomb material Tb2Ir3Ga9. In four different models for the magnetization of a single honeycomb layer, the only sources of anisotropy are symmetric exchange interactions Jnαβ=Jnβα along three different bonds n, an anisotropic g̲ tensor, and a Dzyalloshinskii-Moriya interaction (asymmetric exchange) that produces the observed canted moment along b. With 21 parameters, the best such model yields χ2=0.065, which is substantially smaller than χ2=0.112 obtained using a Heisenberg model containing six parameters including easy-axis anisotropy. However, models without SIA fail to reproduce the linear dependence of the magnetization with a field perpendicular to the Ising axis while predicting a saturation magnetization that is far too low. Due to the complex crystal-field environments, we argue that SIA is necessary to study low-symmetry, three-dimensional Jeff=1/2 materials containing Tb3+ ions.
Original language | English |
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Article number | 020346 |
Journal | Physical Review B |
Volume | 103 |
Issue number | 21 |
DOIs | |
State | Published - Jun 1 2021 |
Funding
The authors would like to acknowledge useful conversations with A. Chernyshev, J. Gardner, M. Khan, J. Mitchell, M. Whangbo, F. Ye, and V. Zapf. Research was sponsored by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division.