The effect of structural disordering on the transport properties of LiNiO2 was studied over wide ranges of temperatures and oxygen pressures.
From the analysis of NQR spectra for Cu and on the basis of investigations of high-temperature electrical conductivity and thermal e.m.f. depending on oxygen pressure and temperature it is shown that in YBa 2 Cu 3 O 7−δ there are pair correlations of the oxygen atoms which lead to formation of the ( O 2)z− pairs, the charge of which is determined by deviation from stoichiometry.
The influence of partial oxygen pressure on the electrical conductivity and the Seebeck coefficient of the high-temperature superconductor YBa 2 Cu 3 O 7−δ is investigated in the temperature range 220–900°C. The relation between non-stoichiometry, mechanism of conductivity and the type of electrical charge carriers is discussed.