Boundary conditions at the interface of finite thickness between ferromagnetic and antiferromagnetic materials

Systematic approach has been applied to obtain the boundary conditions for magnetization at an interface between ferromagnetic (FM) and antiferromagnetic (AFM) materials in the continuous medium approximation. Three order parameters are considered inside an interface of finite thickness magnetization $\mathbf{\text{M}}$ of FM, magnetizations of both sublattices $\mathbf{\text{M}}₁$ and $\mathbf{\text{M}}₂$ of AFM. The boundary conditions are defined in terms of some average properties of the FM/AFM interface. The interface has a finite thickness which is much less than spin wave length. This approach allowed to take into account the interface anisotropy, interface symmetric exchange coupling and interface coupling resulting from inversion symmetry breaking in the vicinity of the interface.