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P Dong Au NPs magnetism 22-JUL-2020.pdf (3.75 MB)

Tuning the Magnetism of Gold Nanoparticles by Changing the Thiol Coating

preprint
submitted on 22.07.2020 and posted on 23.07.2020 by Pengcheng Dong, Elizabeth A. Fisher, Maria-Victoria Meli, Simon Trudel
Room-temperature ferromagnetic behaviour has been reported in nanoscaled materials excepted to be diamagnetic, including gold. However, it is yet unclear which factors (size, shape, surface coating) predominantly influence the magnitude of the magnetic response. In this work, we study the magnetic and electronic properties of similarly-sized gold nanoparticles (Au NPs) coated with four different n-alkanethiols, as well as hydroxyl- and carboxyl-functionalized alkanethiols using superconducting quantum interference device (SQUID) magnetometry and ultraviolet photoelectron spectroscopy (UPS). We find room-temperature behaviour (hysteresis in magnetization vs field strength loops) in all samples, as well as large effective magnetic anisotropy. Importantly, we find the nanoparticles coated with polar chain end-groups (-OH and -COOH) show markedly higher magnetization; this increased magnetization correlates with a higher work function. This work establishes chemical handles to enhance magnetism in nanoscale gold particles.

Funding

NSERC Discovery Grant

History

Email Address of Submitting Author

trudels@ucalgary.ca

Institution

University of Calgary

Country

Canada

ORCID For Submitting Author

0000-0001-5757-2219

Declaration of Conflict of Interest

no conflicts

Version Notes

initial version

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