Electron paramagnetic resonance studies of point defects in diamond : quantification, spin polarisation and preferential orientation

• Main Author: Breeze, Ben G.
• Published: University of Warwick 2016
• Subjects: 553.8; QC Physics
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720455

This thesis reports research on point defects in synthetic single crystal diamond. The principal technique used for investigation is electron paramagnetic resonance, EPR. Nuclear magnetic resonance, NMR, and optical absorption spectroscopy have also been employed. Uniaxial stress has been used to investigate the properties and migration of defects under an applied perturbation. The use of field modulated rapid passage EPR, RP-ERP(FM), for quantitative measurements of neutral single substitutional nitrogen, N⁰_s, in diamond has been investigated. Optimisation of field sweep rate and experiment temperature have been shown to provide a factor of 5.6 improvent in signal to noise; a x25 speed up on previous conditions. The repeatability of RP-EPR(FM) has been investigated by repeated measurements of the same sample (containing N⁰_s). These results indicate a random error of ±2.5%; a 50% reduction compared with slow passage EPR, SP-EPR. Careful cavity characterisation has been utilised to enable reliable quantitative measurements of diamond samples that are large compared to an EPR cavity.