Tunable High-Frequency Properties of Co-Ni Ferromagnetic Nanowires Through Composition Modulation

High-frequency properties of Co-Ni ferromagnetic nanowires with different compositions were investigated in this paper. Co-Ni nanowires including Ni, Co₃₈Ni₆₂ , Co₅₀Ni_50, Co₇₂Ni₂₈, and Co were synthesized in anodic aluminum oxide templates by electrodeposition. The ferromagnetic resonance (FMR) frequency of nanowires was measured by a vector network analyzer with a coplanar waveguide line. Without an external magnetic field, the FMR frequency of the Co-Ni nanowires monotonically increased from 11.0 to 21.5 GHz when the Co content increased from 0 to 100 at.%. With an applied magnetic field of 9.0 kOe, the FMR frequency also linearly rose from 30.0 to 37.5 GHz with increasing the Co content. The experimental data showed that the high-frequency properties of Co-Ni nanowires were linearly tuned through composition modulation, which provided a feasible approach to adjust the working frequency of radio frequency or microwave micro-devices without the assistance of an external magnetic field.