interaction is not so pronounced, as in Fig. 1. Quantitatively, from Fig. 2(a) it follows that at separations 0.5, 2 and 6 µ m η p F , Co varies from –8.9% to –17% and –10%, respectively. From Fig. 2(b) one finds that the values of η p P, Co at the same separations are –6%, –17% and –14%. Thus, if the plasma model is used, the inclusion of magnetic properties decreases the magnitudes of the Casimir free energy and pressure. It is important to note that the dashed lines in Fig. 2(a,b) are very close to the solid lines in Fig. 1(a,b) (the relative differences are below 2.5%). This means that experimentally it is hard to resolve between the case when the metal of the plates is described by the Drude model and magnetic properties influence the Casimir interaction and the case when metal is described by the plasma model but magnetic properties have no impact on the Casimir interaction. Another ferromagnetic metal is Fe. We consider the role of magnetic interactions for two parallel plates made of Fe with the parameters [52, 60] µ$_{Fe}$ (0) = 10 $^{4}$, ω$_{p,}$$_{Fe}$ = 4 . 09 eV and γ$_{Fe}$ = 0 . 018 eV. Numerical computations were performed as described above using Eqs. (1) and (5). The computational results for the Casimir free energy (a) and pressure (b) obtained on the basis of the Drude model approach at T = 300 K are presented in Fig. 3. As above, the solid lines are computed taking into account the magnetic properties of Fe and dashed lines with magnetic properties disregarded. As is seen in Fig. 3, magnetic properties significantly increase the magnitudes of the Casimir free energy and pressure. Thus, at a = 0 . 5, 2 and 6 µ m the respective correction factors vary as η D F , Fe = 18%, 68%, 100% and η D P, Fe = 13%, 47%, 99%. In Fig. 4(a,b) similar computational results for the two Fe plates are presented when the plasma model is used for the description of dielectric properties. It can be seen that for Fe described by the plasma model the influence of magnetic properties on the Casimir interaction is much stronger than for Co using the same model. For separations a = 0 . 5, 2 and 6 µ m respective values of the correction factors are: η p F , Fe = − 3 . 5%, –31%, –42% and η p P, Fe = 0 . 21%, –21%, –45%. In the limiting case of large separations the Casimir interaction between two plates made of ferromagnetic metal can be found analytically. In this case the zero-frequency term alone determines the total result. When dielectric properties are described by the Drude model, both reflection coefficients at zero frequency (10) and (11) do not depend on k ⊥ . Substituting 12