Spatially Resolved Spin–Lattice Relaxation Times and Line Widths in Manganese-Grafted Detonation Nanodiamonds

Abstract

We report on a novel approach that allows determining the spatially resolved nuclear spin–lattice relaxation times and NMR line widths in nanomaterials. The approach was applied to a newly synthesized nanomaterial─detonation nanodiamonds with manganese ions directly grafted to the surface of the nanodiamond particles. The interaction of the carbon nuclear spins with paramagnetic Mn2+ ions results in acceleration of nuclear spin–lattice relaxation and broadening of the 13C resonance line. Using spin dephasing experiments, we were able to determine the layer-by-layer contributions of the paramagnetic Mn2+ions to the spin–lattice relaxation time and line width of the carbon spins positioned at different depths from the diamond surface. Developed for nanodiamonds, this approach is more general and can be successfully applied to study the distribution of nuclear relaxation rates and line broadening and for mapping magnetic interactions inside various nanoparticles, being of practical use in various nanotechnologies.