Tailoring magnetization reversal of a single-domain bar nanomagnet via its end geometry

Abstract

Nanoscale single-domain bar magnets are building blocks for a variety of fundamental and applied mesoscopic magnetic systems, such as artificial spin ices, magnetic shapemorphing microbots as well as magnetic majority logic gates. The magnetization reversal switching field of the bar nanomagnets is a crucial parameter that determines the physical properties and functionalities of their constituted artificial systems. Previous methods on tuning the magnetization reversal switching field of a bar nanomagnet usually rely on modifying its aspect ratio, such as its length, width and/or thickness. Here, we show that the switching field of a bar nanomagnet saturates when extending its length beyond a certain value, preventing further tailoring of the magnetization reversal via aspect ratios. We showcase highly tunable switching field of a bar nanomagent by tailoring its end geometry without altering its size. This provides an easy method to control the magnetization reversal of a single-domain bar nanomagnet. It would enable new research and/or applications, such as designing artificial spin ices with additional tuning parameters, engineering magnetic microbots with more flexibility as well as developing magnetic quantum-dot cellular automata systems for low power computing.

Control of vortex chirality in a symmetric ferromagnetic ring using a ferromagnetic nanoelement

“…This means that the magnetization reversal process of the NE will occur at different magnetic fields compared to the NR. 38 Furthermore, it is important to note that the coupled NR–NE system significantly alters the value of the NE switching field; it changes from H S = 94 mT to H S = 126 mT.…”

Josephson current-assisted reversal of a single-domain nanoscale ferromagnet driven by cosine chirp pulse

“…At low temperatures, due to their long magnetization relaxation time [12], nanomagnets (NMs) are considered as a potential candidate for qubit circuits [13,14] as well as spintronic devices [15,16]. Therefore, the magnetization reversal of single-domain magnetic nanoparticles is important for both fundamental physics and applications [17][18][19]. Various mechanisms have been proposed to achieve the magnetization switching, such as the dc magnetic field and the microwave field with constant frequency, both of which showed long switching time, and the field magnitude should be larger than the anisotropy or coercivity field to energetically stabilize the reversed state [20,21].…”