BISTABLE CONDUCTION ELECTRON-SPIN-RESONANCE IN METALLIC LITHIUM PARTICLES

This paper reports the study by electron spin resonance (ESR) and elec tron nuclear double resonance (ENDOR) of lithium particles in Li2O pow ders irradiated by 1-MeV electrons. The metallic lithium particles are characterized by a narrow ESR line (Delta B-pp = 0.013 mT) due to con duction electrons and an ENDOR signal from Li-7 nuclei interacting wit h these electrons. The ESR of conduction electrons in lithium particle s exhibits a bistable hysteresis of 0.18 mT width at T = 4 K due to st eady-state bistable dynamic nuclear polarization by the Overhauser eff ect, in good agreement with theoretical predictions. The analysis of t he bistable conduction electron spin resonance (BCESR) line shape show ed the existence of two populations of particles differing by their el ectron spin relaxation times T-2 and characterized by a distribution o f nuclear relaxation times.