A novel two microwave field ESR implemented by double field modulation

A theoretical and experimental study of the application of two microwave fi elds to the case of an inhomogeneously broadened electron spin resonance (E SR) line with neglect of spin diffusion is presented. The two microwave fie ld ESR (TMFESR) may be implemented as a simple version of the double-modula tion ESR method provided the modulation index is small. When applied to an inhomogeneously broadened ESR line, the technique yields a response whose w idth is twice the width of the spin packet. The E' defect in gamma-irradiat ed vitreous silica was studied by TMFESR yielding a value of T-2 = 23.6 mu s, in agreement with time-domain ESR measurements. (C) 1999 Elsevier Scienc e B.V. All rights reserved.