Magnetic resonance force spectroscopy of multilayer films Co/Pt with perpendicular magnetic anisotropy

Abstract The magnetic resonance force microscopy (MRFM) in combination with magneto-optical Kerr effect spectroscopy and magnetic force microscopy is used to study ferromagnetic resonance in multilayer thin-film structures [Co(0.5 nm)/Pt(1 nm)]5 with perpendicular magnetic anisotropy. Both the uniformly magnetized state and nonhomogeneous domain structures with different spatial scales are studied. It is shown that labyrinth domain structure manifests itself in the MRFM spectra as specific resonances that are split in an external magnetic field. In zero magnetic field the resonant frequencies depend on the size of oppositely magnetized domains due to internal demagnetizing fields and magnetostatic interaction through overlapping strain fields. For composite sample [Co(0.5 nm)/Pt(1 nm)]5Co(1.3 nm) the decrease in the spatial scale of domain structure and decrease in resonance frequencies are observed, which are due to the effect of interface exchange field. The obtained results demonstrate the ability of MRFM to study the resonance properties of highly inhomogeneous magnetic states of ferromagnetic structures, especially in zero magnetic fields.