Electron Spin Resonance in Semiconducting Diamonds

Abstract

Electron spin resonance (ESR) was studied in five semiconducting diamonds in the temperature range 108°–370°K and at 4.2°K. The g factor is 2.0030±0.0003, and the linewidth varies from 0.3 to 8 Oe at room temperature. The number of spins contributing to the ESR absorption varies between 10¹³–10¹⁴ and agrees with the number of uncompensated acceptors in the case of two diamonds on which Hall and resistivity measurements were made. The number of spins varies as 1/T in the temperature range 108°–370°K. The spin‐lattice relaxation time was estimated to be of the order of 10⁻⁸ sec at 300°K. The results indicate that the spin center is associated with the acceptors in the p‐type diamonds. The effect of heat treatment on the ESR absorption (g=2.0029) observed in crushed nonconducting diamond was measured. The intensity and linewidth (2.9 Oe) for the crushed diamond was reduced on heating at 600°C; further heating at 1100°C did not change the ESR line after the initial decrease.