Objective-first sorting and time resolved diamond magnetic microscopy of superparamagnetic nanoparticles

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Nontechnical abstract: Magnetic nanoparticle research has seen a flurry of activity in recent years, owing to potential applications in biomedical imaging and nanotechnology. However there is presently a lack of tools for quantitative magnetic measurements of individual nanoparticles. The goal of this research is to develop new strategies for high throughput, high spatio-temporal resolution characterization of individual magnetic nanoparticles. The magnetic properties of thousands of individual nanoparticles are simultaneously characterized using a new type of magnetic microscope based on synthetic diamond chips. Unlike existing techniques, the diamond-chip platform works at room temperature and offers high throughput (greater than 1000 individual particles per 10 min). The project aims to correlate magnetic measurements for each individual nanoparticle with its composition, size, shape, and structure. Finally, the proposed research also aims to educate and train diverse groups of high school students, undergraduates, and graduate students, including under-represented groups. Technical abstract. The goal of this research is to develop alternative strategies for high-sensitivity, parallel characterization of individual magnetic nanoparticles. The research project aims to study the magnetic dynamics of superparamagnetic iron oxide nanoparticles with 15-25 nm diameter, with a goal of improving their applicability in nanoscience applications. The magnetic properties of thousands of individual nanoparticles are simultaneously characterized using a magnetic microscope based on color centers doped near the surface of a diamond chip. Correlative transmission electron microscopy and magnetic images of numerous individual nanoparticles is used to elucidate the relationship between nanoparticle size, shape, magnetization relaxation, and hysteresis curve properties. A second aim of this research project is to study the correlation of composition, morphology, and magnetic dynamics of small transition metallic magnetic nanoparticles with a size range (2-10 nm) and establish a fundamental understanding of the effect of size, surface structure, and inter-particle dipolar interactions on their magnetic properties. The target magnetic sensitivity of 10 nT in 1 second integration time for a 400 nm x 400 nm pixel is sufficient to characterize particles down to 2 nm in diameter.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.