Work

High-sensitivity planar Hall effect micro-magnetometry for probing weak magnetic responses of gold nanoparticles at room temperature

Year: 2026

Type: article

Abstract: emu, under the present experimental conditions, enabling measurements on samples containing approximately 2 µg of AuNPs. Two nanoparticle sizes (3.4 nm and 5.0 nm) and two surface states (bare and thiol-terminated polyethylene glycol (PEG-SH)-functionalized) were investigated. Real-time measurements performed during droplet evaporation reveal reproducible differences in the detected magnetic response as the solvent contribution progressively disappears. Smaller nanoparticles exhibit stronger responses than larger particles, while PEG-SH functionalization results in a larger response than the corresponding bare AuNPs. These trends are consistent with previously reported size- and surface-dependent magnetic effects in gold nanoparticle systems and suggest a significant contribution of nanoscale surface effects and interfacial interactions. Overall, the results demonstrate that PHE-based micro-magnetometry provides a highly sensitive, compact, and room-temperature-compatible approach for detecting and comparatively investigating weak magnetic responses from nanoscale materials using microgram-scale sample quantities. Beyond its instrumental capability, the observed size- and surface-dependent variations provide additional insights into the factors influencing weak magnetic responses in gold nanoparticles, highlighting the importance of surface-related effects and nanoparticle organization. This platform complements conventional magnetometry techniques and offers new opportunities for the experimental investigation of weak magnetic phenomena in nanoscale magnetic systems.

Source: Nanoscale

DOI: 10.1039/d6nr01936f