Electron spin resonance techniques were used to detect lattice defects in the nitride lattice. The electron spin resonance spectra were obtained from polycrystalline samples with various thermal conductivities. Measurements of the g-values clearly indicated that the electron spin resonance signals arose from electrons which were trapped by N vacancies. The study revealed that the thermal conductivity increased with an increase in the number of electrons that were trapped by N vacancies. It was suggested that the thermal conductivity increased with a decreasing concentration of incorporated O impurities in the lattice, and that the concentration of N vacancies varied inversely with the concentration of O impurities.

S.Nakahata, K.Sogabe, T.Matsuura, A.Yamakawa: Journal of the American Ceramic Society, 1997, 80[6], 1612-4