title: (13)C spin-lattice relaxation in nanodiamonds in static and magic angle spinning regimes.
abstract: We report on (13)C nuclear spin-lattice relaxation time (T1) dependence on the magic-angle-spinning (MAS) rate in powder nanodiamond samples. We confirm that the relaxation is caused by interaction of nuclear spins with fluctuating electron spins of localized paramagnetic defects. It was found that T1 is practically not affected by MAS for small particles, while for larger particles with lower defect density T1 is different in static and MAS regimes and reveals elongation with increasing MAS rate. This effect is attributed to suppression of nuclear spin diffusion by MAS. We propose an approach that describes T1 dependence on the MAS rate and allows quantitative analysis of this effect.
authors.affiliation: Institute of Physics, University of Szczecin, 70-451 Szczecin, Poland.
authors.forename: N A
authors.initials: NA
authors.lastname: Sergeev
authors.affiliation: Department of Physics, Ben-Gurion University of the Negev, P. O. Box 653, Be'er Sheva 8410501, Israel. Electronic address: pan@bgu.ac.il.
authors.forename: A M
authors.initials: AM
authors.lastname: Panich
authors.affiliation: Institute of Physics, University of Szczecin, 70-451 Szczecin, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Olszewski
authors.affiliation: International Technology Center, Raleigh, North Carolina 27617, United States.
authors.forename: O
authors.initials: O
authors.lastname: Shenderova
authors.affiliation: Department of Physics, Ben-Gurion University of the Negev, P. O. Box 653, Be'er Sheva 8410501, Israel.
authors.forename: S D
authors.initials: SD
authors.lastname: Goren
keywords: MAS; NMR; Nanodiamond; Spin diffusion