ELECTRON-SPIN-RESONANCE STUDIES IN BETA-FESI2 CRYSTALS

The electron spin resonance studies have been carried out in the tempe rature range 130-300 K on semiconducting beta-FeSi2, single crystals g rown by a chemical vapor transport technique. Two anisotropic doublets with apparent g factors in the range 2.025-2.05 and 1.95-2.03, as wel l as one complex signal having an isotropic g factor of 2.0195 and exh ibiting a five-line hyperfine structure, have been detected. The doubl et signals are believed to arise from spin tripler (S=1) states of, pr esumably, substitutional Ni2+ transition ions, whereas the signal exhi biting the hyperfine structure has been attributed to the spin of a ho le, captured by silicon vacancy and interacting with nuclear spins of four iran atoms in the first shell surrounding of the silicon vacancy. (C) 1996 American Institute of Physics.