Magnetic microstructure and magnetic properties of uniaxial itinerant ferromagnet Fe3GeTe2

Magnetic force microscopy was used to observe the magnetic microstructure of Fe3GeTe2 at 4K on the (001) surface. The surface magnetic structure consists of a two-phase domain branching pattern that is characteristic for highly uniaxial magnets in the plane perpendicular to the magnetic easy axis. The average surface magnetic domain width D-s = 1.3 mu m determined from this pattern, in combination with intrinsic properties calculated from bulk magnetization data (the saturation magnetization M-s = 376 emu/cm(3) and the uniaxial magnetocrystalline anisotropy constant K-u = 1.46 x 10(7) erg/cm(3)), was used to determine the following micromagnetic parameters for Fe3GeTe2 from phenomenological models: the domain wall energy gamma(w) = 4.7 erg/cm(2), the domain wall thickness delta(w) = 2.5 nm, the exchange stiffness constant Lambda(ex) = 0.95 x 10(-7) erg/cm, the exchange length l(ex) = 2.3 nm, and the critical single domain particle diameter d(c) = 470 nm. Published by AIP Publishing.