Spin-wave eigenmodes in single disk-shaped FeB nanomagnet

Abstract

Spin-wave eigenmodes in a disk-shaped FeB nanomagnet were investigated using magnetic tunnel junctions with a FeB magnetic layer and MgO barrier. Noise spectrum measurements for a perpendicularly magnetized junction of 120 nm in diameter showed thermal excitation of distinct spin-wave modes. The measured spectra were compared with analytical calculations and numerical simulations. As a result, the observed modes were classified as spin-wave eigenmodes with various nodal circles and nodal diameter modes by taking into account splitting between directional spin-wave modes originating from dynamic dipolar interaction instead of Dzyaloshinskii-Moriya interaction. These results provide a fundamental understanding of spin dynamics in nanosize spintronic devices. © 2016 American Physical Society.