1H NMR studies on the effects of annealing on chemical-vapor-deposited (CVD) diamond

Abstract

A proton nuclear magnetic resonance (1H NMR) spectrum of diamond produced by chemical vapor deposition typically exhibits both a narrow lorentzian and a broad gaussian line. The spin-lattice relaxation time constants of the two components are different in one sample and vary from sample to sample. Typical values are in the range of approximately 50 ms to 1 s. There is little or no hydrogen evolution on annealing in a nitrogen atmosphere at temperatures less than 750°C. However, T1 increases on annealing and the line shape changes as the contribution due to the narrow component decreases. The magnetization recovers as M = M0[1 - exp( - t T1)n], where 0.5 ≤ n ≤ 1. The values of n and T1 increase with annealing indicating a change in the number of relaxation centers present in the sample.

Document Type

Article

DOI

https://doi.org/10.1016/0925-9635(93)90042-Z

Publication Date

3-31-1993

Journal Title

Diamond and Related Materials

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