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arXiv · 1508.06959

Magnetic structure and phase stability of the van der Waals bonded ferromagnet Fe3-xGeTe2

Andrew F. May·Stuart Calder·Claudia Cantoni·Huibo Cao·Michael A. McGuire
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Abstract

The magnetic structure and phase diagram of the layered ferromagnetic compound Fe$_3$GeTe$_2$ has been investigated by a combination of synthesis, x-ray and neutron diffraction, high resolution microscopy, and magnetization measurements. Single crystals were synthesized by self-flux reactions, and single crystal neutron diffraction finds ferromagnetic order with moments of 1.11(5)$μ_B$/Fe aligned along the $c$-axis at 4K. These flux-grown crystals have a lower Curie temperature $T_{\textrm{c}}\approx$150K compared to crystals previously grown by vapor transport ($T_{\textrm{c}}$=220K). The difference is a reduced Fe content in the flux grown crystals, as illustrated by the behavior observed in a series of polycrystalline samples. As Fe-content decreases, so does the Curie temperature, magnetic anisotropy, and net magnetization. In addition, Hall effect and thermoelectric measurements on flux-grown crystals suggest multiple carrier types contribute to electrical transport in Fe$_{3-x}$GeTe$_2$ and structurally-similar Ni$_{3-x}$GeTe$_2$.

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Andrew F. May, Stuart Calder, Claudia Cantoni, Huibo Cao, Michael A. McGuire. 2015-12-21. Magnetic structure and phase stability of the van der Waals bonded ferromagnet Fe3-xGeTe2. https://doi.org/10.1103/physrevb.93.014411

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