Boundary conditions for spin-wave absorption based on different site-dependent damping functions

Finite-difference time-domain techniques applied to nonconfined geometries impose the numerical implementation of computational areas smaller than the physical ones, so that it is necessary to develop a method for the waves absorption at the artificial boundaries. Due to the impossibility to implement some sort of analytical Higdon-type operators within a micromagnetic framework for point-contact geometries, two different absorbing boundary conditions are proposed. They are based on different site-dependent damping functions, whose value rises either abruptly or smoothly close to the computational boundaries. In this paper, it is first tested their robustness and then pointed out their effectiveness in reducing the rate of wave reflection of about three orders of magnitude in some cases.