Light-induced ferromagnetic resonance shift in magnetoelectric heterostructure

The resonant control of the spin magnetic moment using ferromagnetic resonance (FMR) could enable an energy-efficient route for low-power spintronic devices for neuromorphic and signal processing applications. However, resonant spin control by FMR usually requires a rf magnetic field or high-density spin-polarized current resulting in high power consumption. Instigating FMR directly with an external electric field using magnetoelectric (ME) materials can offer an energy-efficient alternative due to large strain-mediated ME coupling. Yet, this method requires a high-saturation electric field that could cause device malfunction due to dielectric breakdown. Also, the necessity to make electrical contacts in ME materials leads to complexity. In this work, we demonstrate light-induced FMR tunability in Ni/PMN-PT ME heterostructure at room temperature. We show that light generates piezostrain in PMN-PT without any bias voltage and controls the spin dynamics of the ferromagnetic Ni thin film. Depending on the direction of the external applied magnetic field with respect to the PMN-PT crystalline directions, upward and downward volatile FMR shift is demonstrated. We also show that FMR shift can be induced by increasing the irradiation time at constant illumination power. This technique presents a remote means to control the spin magnetic moment for next-generation light-controlled ME-based rf and microwave devices, allowing easier integration of these devices into complex architectures by eliminating the need for direct electrical contacts or bulky external components.