Evidence for Partial Surface Spin Pinning in Ferromagnetic Resonance

Abstract

Spin‐wave‐resonance measurements of 81%‐Ni–19%‐Fe evaporated films 30–9000 Å thick at frequencies from 1 to 8 GHz, at room temperature and with the static magnetic field parallel and perpendicular to the film have been performed. The resonance spectra of both geometries are for the first time uniquely explained by the excitation of partially pinned spin‐wave modes with A=(1.03±0.05)×10⁻⁶ erg/cm. The resonance fields for both cases are thickness dependent and consistent with a thickness‐dependent demagnetizing field caused by film surface roughness.