Magnetic Field Mapping Around Individual Magnetic Nanoparticle Agglomerates Using Nitrogen‐Vacancy Centers in Diamond

A modified diamond–photonics based metrology is proposed to explore the magnetic fields created by agglomerates of nanoparticles (MNPs). MNPs are promising for environmental and medical applications; those cancer hyperthermia treatments small superparamagnetic <20 nm iron oxide particles. Inside cells, they assemble in larger MNP agglomerates, reaching cross-sections several micrometers. Here, these conditions reproduced immobilized. Optically detected resonance (ODMR) signals recorded without a bias field confocal microscope scanning across homogenous shallow layer fluorescent nitrogen-vacancy centers bulk diamond sample placed direct contact with used determine spatial resolution 500 lateral direction. This allows determining maps around individual which strengths ranging from 0.03 mT maximal 1.2 vicinity detectable up 5 µm away determined. Based on findings, pathway non-invasively study micro/nano topology proposed.