Temporal evolution of auto-oscillations in a YIG/Pt microdisc driven by pulsed spin Hall effect-induced spin-transfer torque

TL;DR

This study investigates the time-dependent behavior of auto-oscillations in a YIG/Pt microdisc driven by pulsed spin Hall effect-induced spin-transfer torque, revealing frequency differences and saturation dynamics crucial for future spintronic devices.

Contribution

It provides the first experimental analysis of the temporal evolution of SHE-STT driven auto-oscillations in YIG/Pt microdiscs using time-resolved BLS spectroscopy.

Findings

Frequency varies between center and edge of the disc.

Magnetization precession saturates after 20 ns or more.

Proper current and pulse duration ratio is vital for device optimization.

Abstract

The temporal evolution of pulsed Spin Hall Effect - Spin Transfer Torque (SHE-STT) driven auto-oscillations in a Yttrium Iron Garnet (YIG) / platinum (Pt) microdisc is studied experimentally using time-resolved Brillouin Light Scattering (BLS) spectroscopy. It is demonstrated that the frequency of the auto-oscillations is different in the center and at the edge of the investigated disc that is related to the simultaneous STT excitation of a bullet and a non-localized spin-wave mode. Furthermore, the magnetization precession intensity is found to saturate on a time scale of 20 ns or longer, depending on the current density. For this reason, our findings suggest that a proper ratio between the current and the pulse duration is of crucial importance for future STT-based devices.