Magnetic Properties of Layered Itinerant Electron Ferromagnet Fe3GeTe2

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 chi(T), isotherm magnetization M(H), specific heat C(T), and electrical resistivity rho(T) measurements. The rietveld refinement of the powder XRD data confirms that Fe3GeTe2 crystallizes in the space group p6(3)/mmc. The chi(T), C(T), and rho(T) data indicate bulk ferromagnetic ordering at T-C = 220 K with a saturation moment of 1.625 mu(B)/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.