93Nb NQR spectra in compounds with the A-15 structure on the basis of niobium

Quadrupole interactions in Nb3X(X=Os, Ir, Pt) compounds with A-15 structure are determined by the nuclear quadrupole resonance method. The investigated samples represented polycrystalline particles with the size of 20-50 mKm. The measurements were carried out on the nuclear quadrupole resonance pulse spectrometer at the temperatures higher than critical. The 93Nb nuclear quadrupole resonance spectra in the investigated compounds consist of several overlapping lines of essential width. The analysis of the spectra obtained showed essential value of the assymetry parameter of the electric field gradient caused probably by structural manifestation of compound instability