Theory of near-field radiative heat transfer for stratified magnetic media

We report a general model to deal with near-field radiative heat transfer for the layered magnetic media, which is also applicable for layered nonmagnetic media. In the derivation, a method using the reciprocity theorem with dyadic Green's function (DGF) and transfer matrix is introduced, which make the expressions simple and compact. By means of multiple reflection diagrams, it is clear to understand the physical interpretation of DGF and it is easy to evaluate it with physical picture for simple construction. Finally, the expression for the near-field radiative heat transfer between two semi-infinite solids separated by a medium is given as an example. Some numerical computations are conducted for both non-magnetic and magnetic media, which reveals the validity of the derived expressions and the difference between the two types of materials from the point of view of near-field radiative heat transfer. Furthermore, the results indicate that the near-field radiative flux will be further enhanced by excitation of surface polaritons in TE polarization for magnetic media.