Boundary Pinning Effects on the Frequency Spectra of Point-Contact Spin-Torque Oscillators

Micromagnetic simulation is used to investigate the frequency spectra of a perpendicularly magnetized nanocontact spin-torque oscillator subject to different boundary pinning conditions. Boundary confinement is critical to the output spectra: spectra under two limiting conditions are attributed to the different pinning strengths at the boundaries. The correlation between boundary pinning strength and output spectra may facilitate the design of future nanocontact microwave devices.