Magnetic Field-Controlled THz Modulation in Uniaxial Anisotropic Spin-Valves Emitters

TL;DR

This paper demonstrates magnetically tunable THz emission in a uniaxial spin-valve heterostructure, enabling efficient, low-field control of THz amplitude through reversible magnetization switching and interference effects.

Contribution

It introduces a wafer-compatible spin valve device architecture for tunable THz emission, combining experimental magnetometry, phase analysis, and modeling to understand and control the emission mechanisms.

Findings

Reversible switching between magnetization states correlates with emission regimes.

Constructive and destructive interference modulates THz amplitude.

A macrospin model reproduces field dependence and layer contributions.

Abstract

Uniaxial spintronic heterostructures constitute compact THz emitters under femtosecond optical excitation, with emission amplitude and polarization governed by the applied magnetic field is presented. We demonstrate here efficient magnetically tunable THz amplitude control in ultrathin, exchange-biased Co/Pt/Co/IrMn spin valve. Terahertz spintronic magnetometry resolves reversible switching between parallel and antiparallel magnetization states and correlates the high- and low-emission regimes with constructive and destructive interference of charge transients generated by the inverse spin Hall effect in the Pt spacer. A residual low-emission signal is traced to spin-to-charge conversion in IrMn. Phase inversion under front- versus back-side excitation confirms the ISHE origin of the emission, while a macrospin Landau-Lifshitz-Gilbert model reproduces the field dependence of its amplitude and separates layer-specific contributions. Together, these results define a wafer-compatible spin valve device architecture that enables efficient, low-field THz amplitude control.