Effect of Fe3O4 Nanoparticles on CoFeB/Ta/CoFeB Spin-Valve Magnetoresistance Probed by Microwave Absorption

The effect of nanoparticles (NPs) on microwave magnetoresistance in MgO/CoFeB(free)/Ta/CoFeB(fixed)/MgO)/Ta platform and the effect of individual NP on free CoFeB ferromagnetic layer magnetization have experimentally been revealed and analyzed. The area of the platform where magnetization is inverted under scattering field of NPs has been observed. Micromagnetic modeling of dipole magnetic interaction confirms the existence of such areas in “NP-platform” system. The increase in critical field of the platform and the change of resistance under scattering field on NPs have experimentally been revealed.