Low-Temperature Magnetism of Gold Nano Particles Contained in Electrochemical Sugar Recognition System

• Published in: IEEE transactions on magnetics Vol. 55; no. 2; pp. 1 - 4
• Main Authors: Goto, T., Kitamoto, Y., Matsui, K., Kuroe, H., Endo, A., Hashimoto, T., Hayashita, T., Iguchi, S., Sasaki, T.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Diamagnetism; Economic indicators; Gold; Gold nano particles (GNPs); Low temperature; Magnetic permeability; Magnetic properties; Magnetic susceptibility; Magnetism; NMR; Nuclear magnetic resonance; nuclear magnetic resonance (NMR); paramagnetism; Ruthenium compounds; Temperature dependence; Temperature measurement
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2018.2872134

Low-temperature magnetic properties were investigated on the gold nano particles (GNPs) with an average size of 11.5 nm, assembled with molecules of ruthenium complex (Ru0), and phenylboronic acid (B0) by the proton nuclear magnetic resonance ( 1 H-NMR) and susceptibility measurements. The temperature dependence of the NMR shift and the uniform susceptibility was described as the sum of the Curie-Weiss term and a positive constant term. From the former, the average number of Ru0 on each GNP was estimated to be 118, which is 23% of the calculation. The finite positive constant term shows a clear contrast with the well-known fact that the bulk gold is diamagnetic. Finally, a disappearance of the motional narrowing effect in the proton NMR spectra below 60 K indicates that the wavering motion of Ru0 complexes on GNP at room temperature is frozen at low temperatures.