Control of the Oscillatory Interlayer Exchange Interaction with Terahertz Radiation

TL;DR

This paper demonstrates that terahertz radiation can dynamically control the oscillatory interlayer exchange interaction in magnetic multilayers, enabling switching between ferromagnetic and anti-ferromagnetic states.

Contribution

It provides a theoretical framework linking the dynamical exchange interaction under terahertz radiation to the well-measured static interaction, offering a new method for magnetic control.

Findings

Exchange interaction can be tuned from ferromagnetic to anti-ferromagnetic.

Radiation amplitude and frequency control the interaction state.

Theoretical expression relates dynamic and static exchange interactions.

Abstract

The oscillatory interlayer exchange interaction between two magnetic layers separated by a metallic spacer is one of the few coherent quantum phenomena that persist at room temperature. Here we show that this interaction can be controlled dynamically by illuminating the sample (e.g. a spin valve) with radiation in the 10-100 THz range. We predict that the exchange interaction can be changed from ferromagnetic to anti-ferromagnetic (and vice versa) by tuning the amplitude and/or the frequency of the radiation. Our chief theoretical result is an expression that relates the dynamical exchange interaction to the static one that has already been extensively measured.