Magnetic Properties of Layered Itinerant Electron Ferromagnet Fe₃GeTe₂

Abstract

We have successfully synthesized a single-crystal sample of the layered structure ferromagnet Fe3GeTe2 and present the results of its complete characterization using powder X-ray diffraction (XRD), magnetic susceptibility χ(T), isotherm magnetization \(M(H)\), specific heat \(C(T)\), and electrical resistivity ρ(T) measurements. The rietveld refinement of the powder XRD data confirms that Fe3GeTe2 crystallizes in the space group \(p6_{3}/mmc\). The χ(T), \(C(T)\), and ρ(T) data indicate bulk ferromagnetic ordering at \(T_{\text{C}} = 220\) K with a saturation moment of 1.625 µB/Fe at zero temperature. The magnetic measurements of the external magnetic field \(H\) applied along the \(c\)-axis and \(ab\)-plane show a large anisotropy in this material. We found that the modified Arrott plot (\(M^{4}\)–\(H/M\)) rather than the \(M^{2}\)–\(H/M\) plot is obeyed in this material. The generalized Rhodes–Wohlfarth ratio indicates an itinerant magnetism in this material. The spin fluctuation parameters are estimated and the magnetic properties are discussed in the framework of the self-consistent renormalization (SCR) and Takahashi theory of spin fluctuations.