Individually grown cobalt nanowires as magnetic force microscopy probes

Reliable preparation and regeneration of well-defined single-atom tips through laser annealing

Single-atom tips (SATs) have crucial scientific and technological applications, such as in scanning probe microscopy and charged particle beam technology. We reported a reliable method of preparing and regenerating noble metal-covered W(111) SATs through laser annealing at approximately 1000 K under ultrahigh vacuum. The field emission patterns obtained during laser heating revealed the self-assembly process of a pyramidal tip. The SATs can be regenerated through laser annealing tens of times with little change in sharpness, indicating a long lifetime. Various pyramidal SATs can be generated and regenerated using visible-light, near-infrared, mode-locked, and continuous-wave lasers at different polarizations relative to the tip axis. The generation of well-defined pyramidal SATs through laser annealing can facilitate various applications of SATs.

Magnetic Functionalization of Scanning Probes by Focused Electron Beam Induced Deposition Technology

The fabrication of nanostructures with high resolution and precise control of the deposition site makes Focused Electron Beam Induced Deposition (FEBID) a unique nanolithography process. In the case of magnetic materials, apart from the FEBID potential in standard substrates for multiple applications in data storage and logic, the use of this technology for the growth of nanomagnets on different types of scanning probes opens new paths in magnetic sensing, becoming a benchmark for magnetic functionalization. This work reviews the recent advances in the integration of FEBID magnetic nanostructures onto cantilevers to produce advanced magnetic sensing devices with unprecedented performance.

Ultralow magnetostrictive flexible ferromagnetic nanowires

The integration of magneto-electric and spintronic sensors to flexible electronics presents a huge potential for advancing flexible and wearable technologies. Magnetic nanowires are core components for building such devices. Therefore, realizing flexible magnetic nanowires with engineered magneto-elastic properties is key to flexible spintronic circuits, as well as creating unique pathways to explore complex flexible spintronic, magnonic, and magneto-plasmonic devices. Here, we demonstrate highly resilient flexible ferromagnetic nanowires on transparent flexible substrates for the first time. Through extensive magneto-optical Kerr experiments, exploring the Villari effect, we reveal an ultralow magnetostrictive constant in nanowires, a two-order reduced value compared to bulk values. In addition, the flexible magnetic nanowires exhibit remarkable resilience sustaining bending radii ∼5 mm, high endurance, and enhanced elastic limit compared to thin films of similar thickness and composition. The observed performance is corroborated by our micro-magnetic simulations and can be attributed to the reduced size and strong nanostructure-interfacial effects. Such stable magnetic nanowires with ultralow magnetostriction open up new opportunities for stable surface mountable and wearable spintronic sensors, advanced nanospintronic circuits, and for exploring novel strain-induced quantum effects in hybrid devices.