Magnetic skyrmions are of great interest to both fundamental research and applications in post-von-Neumann computing devices. The successful implementation of skyrmionic devices requires functionalities of skyrmions with effective controls. Here we show that the local dynamics of skyrmions, in contrast to the global dynamics of a skyrmion as a whole, can be introduced to provide effective functionalities for versatile computing. A single skyrmion interacting with local pinning centres under thermal effects can fluctuate in time and switch between a small-skyrmion and a large-skyrmion state, thereby serving as a robust true random number generator for probabilistic computing. Moreover, neighbouring skyrmions exhibit an anti-correlated coupling in their fluctuation dynamics. Both the switching probability and the dynamic coupling strength can be tuned by modifying the applied magnetic field and spin current. Our results could lead to progress in developing magnetic skyrmionic devices with high tunability and efficient controls.

The interfacial Dzyaloshinskii-Moriya interaction (DMI) holds promises for design and control of chiral spin textures in low-dimensional magnets with efficient current-driven dynamics. Recently, an interlayer DMI has been found to exist across magnetic multilayers with a heavy-metal spacer between magnetic layers. This opens the possibility of chirality in these three-dimensional magnetic structures. Here we show the existence of the interlayer DMI in a synthetic antiferromagnetic multilayer with both inversion and in-plane asymmetry. We analyse the interlayer DMI’s effects on the magnetization and the current-induced spin-orbit torque (SOT) switching of magnetization through a combination of experimental and numerical studies. The chiral nature of the interlayer DMI leads to an asymmetric SOT switching of magnetization under an in-plane magnetic field. Our work paves the way for further explorations on controlling chiral magnetizations across magnetic multilayers through SOTs, which can provide a new path in the design of SOT devices.

In this work, we demonstrate that interlayer exchange-coupled magnetic thin films can be employed to fabricate ultrasensitive and thermally stable magnetic sensors, taking advantage of the linear anomalous Hall effect via tuning the interlayer exchange coupling and magnetic anisotropy. We investigate the magnetotransport and noise properties of these anomalous Hall sensors. The magnetic field detectability reaches $126.1\mathrm{nT/}\sqrt{\mathrm{Hz}}$ at 1 Hz and $4.5\mathrm{nT/}\sqrt{\mathrm{Hz}}$ at 1 kHz, at room temperature. Meanwhile, the achieved dynamic reserve is 103.0 dB. The magnetic field detectability shows a good temperature stability in the 200 to 300 K range. Within the temperature range, the temperature coefficient of sensitivity is determined to be 530 ppm/K. The high temperature stability is attributed to the interlayer exchange coupling, which also improves the stability against in-plane magnetic fields, beneficial for perpendicular magnetic field sensing. The interlayer exchange-coupled magnetic thin-film-based anomalous Hall sensors solve the trade-off between the sensor size, sensing capability, and stability, which are desirable for microimaging and biomedical applications.

Manipulation of magnetic skyrmions has been generating considerable interest because of their potential applications in future spintronic devices. As an information carrier, a skyrmion is used to code a bit. In this work, we study via micromagnetic simulations a three-terminal racetrack memory, where an isolated skyrmion can be generated and annihilated by the gate voltage pulse. Thus, we can modify a train of skyrmion codes written at the generator in a controlled manner. The modified information is then detected at the collector. We have identified both gyration and breathing modes during skyrmion manipulation. The dynamics is analysed via a Thiele equation derived from the micromagnetic model. From the equation, the gyration mode of a skyrmion is suggested to be coupled to the breathing mode dynamics. This work proposes an effective method for controlled modification of skyrmion information in a potential energy-efficient racetrack memory, and provides a fundamental understanding of the intrinsic skyrmion dynamics during skyrmion manipulation.

Spin textures, such as magnetic domain walls and skyrmions, have the potential to revolutionize electronic devices by encoding information bits. Although recent advancements in ferromagnetic films have led to promising device prototypes, their widespread implementation has been hindered by material-related drawbacks. Antiferromagnetic spin textures, however, offer a solution to many of these limitations, paving the way for faster, smaller, more energy-efficient, and more robust electronics. The functionality of synthetic antiferromagnets, comprised of two or more magnetic layers separated by spacers, may be easily manipulated by making use of different materials as well as interface engineering. In this Perspective article, we examine the challenges and opportunities presented by spin textures in synthetic antiferromagnets and propose possible directions and prospects for future research in this burgeoning field.