Metastable fcc structures using ultrathin layers of metastable fcc Co(001) and fcc Cu(001) were grown by molecular-beam epitaxy. The growth was studied using reflection high-energy electron-diffraction (RHEED) patterns and RHEED intensity oscillations. The magnetic properties were investigated by employing ferromagnetic-resonance (FMR) and surface magneto-optic Kerr effect (SMOKE) techniques. A detailed discussion of the underlying physical mechanisms in FMR and SMOKE studies is presented. The temperature and thickness dependences of the perpendicular uniaxial and fourfold in-plane anisotropies are given and discussed. The role of lattice strains in magnetic anisotropies is demonstrated. FMR measurements revealed that the magnetic properties of single Co layers are different from those in Co/Cu/Co trilayers becuase of a lattice-strain relaxation in the multilayer samples. The exchange coupling between fcc Co(001) layers separated by a fcc Cu(001) interlayer was studied for several structures. The exchange coupling in Co structures was found to be anisotropic. Hysteresis loops were measured by means of SMOKE. Magnetic-trilayer hysteresis loops are complex. Micromagnetic calculations were carried out to explain their main features.

We have grown a new phase of Cu, bcc Cu, on bcc Fe(001). We have shown that bcc Cu(001) grows epitaxially on bcc Fe(001) and that bcc Fe(001) grows epitaxially on bcc Cu(001). bcc Cu(001) on Fe(001) maintains its structure for 10–11 monolayers before undergoing a structural transition. Ultrathin well-defined trilayers of Fe(001)/Cu(001)/Fe(001) with Cu thicknesses between 6–12 monolayers were grown. Ferromagnetic resonance, Brillouin light scattering, and surface magneto-optical Kerr effect were used to measure the coupling between the Fe layers. The coupling between the Fe layers changed from ferromagnetic to antiferromagnetic between 9–10 monolayers of Cu.

A new phase of Pd with an expanded lattice (5%) was grown on Fe(001). Ultrathin Fe/Pd and Pd/Fe bilayers and Fe/Pd/Fe trilayers were studied using ferromagnetic resonance and Brillouin scattering. Pd interlayers always couple the Fe layers ferromagnetically. For thicknesses up to four monolayers the Pd is ferromagnetic, in agreement with theory. One additional atomic layer of Pd destroys the ferromagnetism, but the Pd still exhibits a fluctuating magnetic moment partly polarized by the exchange field from adjacent Fe layers. The magnetic moments in the interfaces were determined from the ferromagnetic-resonance absorption intensities.

The ferromagnetic resonance (FMR) linewidth ΔH is a parameter used to characterize ultrathin film quality. The frequency-independent part, ΔH(0), reflects the contribution of magnetic inhomogeneities. The linear part is caused by the intrinsic Gilbert damping mechanism. Recently we have found that the lattice reconstructions of substrate templates strongly affects the FMR linewidth. bcc Fe(001) films (∼10 ML) were grown on unreconstructed fcc Ag(001), bcc Cu(001), and on surface reconstructed bcc Cu(001) templates. Fe layers grown on unreconstructed Cu templates exhibited an isotropic FMR linewidth. Fe layers grown on reconstructed Cu templates, on the contrary, showed an anisotropic behavior in both the zero-frequency FMR linewidth and the intrinsic damping parameter. Other magnetic parameters such as uniaxial and 4-fold anisotropies are also discussed.