High frequency dynamics modulated by collective magnetization reversal in artificial spin ice

TL;DR

This paper investigates high-frequency magnetic dynamics in artificial spin ice using spin-torque ferromagnetic resonance, revealing how collective magnetization reversal influences these dynamics and enabling potential reconfigurable microwave devices.

Contribution

It introduces ST-FMR techniques to artificial spin ice, linking collective magnetic behavior with high-frequency responses and proposing new applications in reconfigurable devices.

Findings

Demonstrated ST-FMR in artificial spin ice

Correlated magnetoresistance with collective magnetic dynamics

Simulated magnetic response highlighting collective effects

Abstract

Spin-torque ferromagnetic resonance (ST-FMR) arises in heavy metal/ferromagnet heterostructures when an alternating charge current is passed through the bilayer stack. The methodology to detect the resonance is based on the anisotropic magnetoresistance, which is the change in the electrical resistance due to different orientations of the magnetization. In connected networks of ferromagnetic nanowires, known as artificial spin ice, the magnetoresistance is rather complex owing to the underlying collective behavior of the geometrically frustrated magnetic domain structure. Here, we demonstrate ST-FMR investigations in a square artificial spin-ice system and correlate our observations to magnetotransport measurements. The experimental findings are described using a simulation approach that highlights the importance of the correlated dynamics response of the magnetic system. Our results open the possibility of designing reconfigurable microwave oscillators and magnetoresistive devices based on connected networks of nanomagnets.