Document Type
Article
Publication Date
7-20-2011
Publication Title
Physical Review B - Condensed Matter and Materials Physics
Department
Department of Physics and Astronomy
Abstract
We investigate the low-field relaxation of nuclear hyperpolarization in undoped and highly doped silicon microparticles at room temperature following removal from high field. For nominally undoped particles, two relaxation time scales are identified for ambient fields above 0.2 mT. The slower, T1,s, is roughly independent of ambient field; the faster, T1,f, decreases with increasing ambient field. A model in which nuclear spin relaxation occurs at the particle surface via a two-electron mechanism is shown to be in good agreement with the experimental data, particularly the field independence of T1,s. For boron-doped particles, a single relaxation time scale is observed. This suggests that for doped particles, mobile carriers and bulk ionized acceptor sites, rather than paramagnetic surface states, are the dominant relaxation mechanisms. Relaxation times for the undoped particles are not affected by tumbling in a liquid solution.
DOI
10.1103/PhysRevB.84.035304
Dartmouth Digital Commons Citation
Lee, M.; Cassidy, M. C.; Ramanathan, C.; and Marcus, C. M., "Decay of Nuclear Hyperpolarization In Silicon Microparticles" (2011). Dartmouth Scholarship. 1933.
https://digitalcommons.dartmouth.edu/facoa/1933
