Spin dynamics in point contacts to single ferromagnetic films

TL;DR

This paper investigates GHz spin dynamics in ferromagnetic point contacts, demonstrating microwave-driven spin-wave excitations and their impact on conductance, highlighting the role of spin transfer torque effects at the ferromagnetic interface.

Contribution

It provides experimental evidence of microwave-induced spin-wave excitations and rectification effects in ferromagnetic point contacts, elucidating spin transfer torque mechanisms.

Findings

Microwave irradiation excites spin-waves in ferromagnetic point contacts.

Resonant stimulation of spin-wave modes by microwaves observed.

Conductance rectification linked to spin-wave nonlinearities.

Abstract

Excitation of magnons or spin-waves driven by nominally unpolarized transport currents in point contacts of normal and ferromagnetic metals is probed by irradiating the contacts with microwaves. Two characteristic dynamic effects are observed: a rectification of off-resonance microwave current by spin-wave nonlinearities in the point contact conductance, and a resonant stimulation of spin-wave modes in the nano-contact core by the microwave field. These observations provide a direct evidence that the magnetoconductance effects observed are due to GHz spin dynamics at the ferromagnetic interface driven by the spin transfer torque effect of the transport current.