Significant Spin-Capacitive Modulation of Magnetism Through Na+ Motion in Layered FeSe

Abstract

Recently, a novel spin-capacitive method has emerged and distinguishes itself in voltage control of magnetism (VCM) through dual-phase ion-electron conduction, exhibiting significant, rapid, and reversible magnetic modulation in several lithium-ion-based devices, with promising potential for low-power applications. Considering the inherent link to neuronal processing, enhanced safety, and superior compatibility with semiconductor integration of sodium-based devices, the first report on magnetization modulation via Na-assisted spin capacitance mechanism is presented, showcasing unique advantages over lithium-based devices. Employing layered FeSe as the regulated material, operando magnetometry demonstrates giant and reversible magnetic modulation, involving On-Off ferromagnetic switching at high voltages and quasi-linear magnetization change at low voltages. Comprehensive analyses confirm the spin capacitance characteristics of VCM in low-voltage regions, achieving a significant modulation amplitude of 12.70 emu g⁻¹ within 1 V. This is facilitated by nearly 100% formation of Fe nanoparticles via the two-step reaction during Na introduction to layered FeSe. Furthermore, spin-capacitive magnetic regulation in the devices exhibits superior manipulative characteristics within the low voltage range of 0–0.75 V, notably robust endurance, rapid response, and non-volatility. This work inspires new avenues for developing low-power devices featuring high speed, reversibility, non-volatility, and cost-effectiveness, especially exhibiting notable advantages in brain-like simulation applications.