Junta Igarashi

Abstract Radiofrequency harvesting using ambient wireless energy could be used to reduce the carbon footprint of electronic devices. However, ambient radiofrequency energy is weak (less than −20 dBm), and the performance of state-of-the-art radiofrequency rectifiers is restricted by thermodynamic limits and high-frequency parasitic impedance.

In this study, we explore the influence of interlayer exchange coupling on magnetization reversal triggered by femtosecond laser pulses in ferromagnetic spin valves. Our experiments, focused on femtosecond laser-induced magnetization reversal, methodically vary the thickness of the copper (Cu) spacer layer. We identify a critical Cu thickness threshold at 2.32 nm. Above this threshold, a stable reversed magnetic domain is consistently generated upon exposure to a single laser pulse.

Abstract Magnetic tunnel junctions (MTJ) exhibit spin-dependent conductance that governs their performance in various applications. While the transport characteristics are known to show nonlinearity, their behavior and underlying mechanism have not yet understood well. Here we investigate nonlinear conductance at a low bias regime in nanoscale MTJs with a perpendicular magnetic easy axis and various junction sizes, by measuring current-voltage (IV) characteristics and ferromagnetic resonance.