Investigation of ultra-thin ferromagnetic films with a simple cubic lattice

摘要

Using Green's function method, we investigate ferromagnetic films with a simple cubic lattice containing up to tenmonolayers. The Hamiltonian includes the Heisenberg exchange term, surface anisotropy (SA) and dipole interaction(DI). We calculate the magnetization as a function of temperature and film thickness, and we analyse the behaviourof spin canting. The result is in agreement with experiments. We calculate phase diagrams of SA versus DI to showthe conditions under which spontaneous magnetization can occur. As a special case, we discuss the Heisenberg modelwithout SA and DI.