Atomic environment; Atomic layer; Atomic regions; Band fillings; Bulk behavior; Fe films; Finite temperatures; Geometrical relaxation; Local magnetic moments; Local magnetization; Magnetization direction; Orbital magnetization; Simple mean-field theory; Slab systems; Small charges; Spin-orbit couplings; Static approximations; Temperature dependence; Temperature effects; Thermal fluctuations; Atoms; Charge transfer; Ion exchange; Magnetic anisotropy; Magnetic moments; Magnetization; Mean field theory; Spin dynamics; Statistical mechanics; Magnetic field effects