Determination of atom charge states in lattices of superconducting metal oxides of copper by 61Cu(61Ni) and 67Cu(67Zn) emission Mössbauer spectroscopy
Abstract
It is shown that for the majority of metal oxides of divalent copper a linear correlation exists between the quadrupolar couplings on 63Cu nuclei (C Cu) (NMR data for the 63Cu isotope), on one side, and 67Zn (C Zn) and 61Ni nuclei (C Ni) (emission Mössbauer spectroscopy data on the 67Cu (67Zn) and 61Cu (61Ni) isotopes), on the other side. This finding indicates the similarity of copper electronic structures in these lattices. Analogous linear relationships exist between C Cu, C Ni, and the calculated values of the principal component of the crystalline electric field gradient for the compounds of divalent copper. The mentioned dependences allow estimating the validity of the models for the charge distribution on the lattice sites proposed for superconducting ceramics.