Spin-wave study of magnetic perpendicular surface anisotropy in single crystalline MgO/Fe/MgO films

Broadband ferromagnetic resonance is measured in single crystalline Fe films of varying thickness sandwiched between MgO layers. An exhaustive magnetic characterization of the films (exchange constant, cubic, uniaxial and surface anisotropies) is enabled by the study of the uniform and the first perpendicular standing spin wave modes as a function of applied magnetic field and film thickness. Additional measurements of nonreciprocal spin-wave propagation allow us to separate each of the two interface contributions to the total surface anisotropy. The results are consistent with the model of a quasi-bulk film interior and two magnetically different top and bottom interfaces, a difference ascribed to different oxidation states.

Automated summary

In this study, broadband ferromagnetic resonance is measured in Fe films to investigate their magnetic properties. The films are sandwiched between MgO layers and their characteristics, such as exchange constant, cubic, uniaxial and surface anisotropies, are analyzed by studying the spin wave modes in applied magnetic fields and varying film thickness. Additional measurements of nonreciprocal spin-wave propagation allow for the separation of each interface contribution to the total surface anisotropy. The experimental results are consistent with the proposed model of a quasi-bulk film interior and two magnetically different interfaces.