The Ferrum Gadolinium (FeGd) material is considered an important alloy because it can induce a uniaxial anisotropy axis in the plane of the film. The alloy of Fe/Gd bilayer is good for use as a material in the manufacture of HDD because it can be applied as a magnetic storage medium with high density and heat resistance. Micromagnetic simulations were performed on antiferromagnetic Gd material, ferromagnetic Fe and Fe/Gd bilayer to determine the Neel temperature value, Curie temperature and hysteresis curve. Simulations were carried out using Vampire software with variations in the size of the side of the cube used, namely 10 nm, 17.16 nm, and 23 nm. The simulation results show in the Fe/Gd bilayer, the Curie temperature value is smaller than the Curie temperature value for ferromagnetic Fe material because there is an antiferromagnetic Gd material which acts as a pinning direction of magnetization in the ferromagnetic layer above it through anisotropy exchange. The characteristics of the hysteresis curve in the bilayer Fe/Gd material produce a smaller coercivity field value than the ferromagnetic Fe material coercivity field. This is due to the addition of an antiferromagnetic layer which greatly affects the magnetic properties of the material.