Effect of seed layers on the static and dynamic magnetic properties of CoIr films with negative effective magnetocrystalline anisotropy

The c-axis oriented hcp-Co₈₁Ir₁₉ magnetic films were prepared on different seed layers (Ni, Cu, Ir, Pt, Au, and No seed). We systematically investigated the impact that surface-free energy and strain energy have on the orientation and defects and/or internal stress of the grains by increasing the lattice mismatch ratio. Moreover, the initial permeability and the natural resonance frequency were discussed in great detail using a comparison between calculated values and experimental values. We found that the almost unchanged 4πM_s and μ_i are not affected, while the changed H_c, intrinsic K_grain, and f_r are strongly dependent on the seed layer and seed layer material. Moreover, the extracted damping constant is sensitive to the defects and/or internal stress and orientation of the grains. Therefore, the soft magnetic properties and microwave properties are adjusted and optimized by seed layers with different materials.