Spin-Spin and spin-lattice relaxation of protons in ferrofluids characterized with a high-Tc SQUID-based NMR spectrometer in microtesla fields

Hong-Chang Yang, Shu-Hsien Liao, Chieh Wen Liu, Hsin Hsien Chen, Herng-Er Horng, K. L. Chen, M. J. Chen, Chieh I. Liu, L. M. Wang

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    1 Citation (Scopus)

    Abstract

    In this work, the relaxation rates of ferrofluids are characterized using a high-Tc SQUID-based nuclear magnetic resonance spectrometer in different field strengths and temperatures. It was found that the longitudinal relaxation rate, 1/T1 , of ferrofluids measured in a high field strength is significantly higher than that measured in a low field strength. We attribute this to the magnetic-field gradients from the magnetization of magnetic nanoparticles that accelerate the T1-relaxation more in a high strength of magnetic fields than they are in a low strength of magnetic fields. Furthermore, T1 and T2 decrease when temperature increases, where T2 is the transverse relaxation time. This is due to the improved field-homogeneity seen by protons' spins at high temperatures, attributed to the enhanced Brownian motion of magnetic nanoparticles. Characterizing the relaxation rates will be helpful for further use of ferrofluids as contrast agents in low-field MR imagings.

    Original languageEnglish
    Article number6399572
    JournalIEEE Transactions on Applied Superconductivity
    Volume23
    Issue number3
    DOIs
    Publication statusPublished - 2013 May 20

    Keywords

    • Ferrofluids
    • NMR/MRI
    • SQUID
    • flux coupling
    • relaxation

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Electrical and Electronic Engineering

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