Magnetic and Electrical Properties, 151Eu M?ssbauer Spectroscopy, and Chemical Bonding of REAgMg (RE=La, Ce, Eu, Yb) and EuAuMg

This work presents a modified defect model for pure and chemically substituted quadruple and quintuple pure perovskite layered cuprates, using data from the Jonker (thermopower vs ln conductivity) and Brouwer (log conductivity vs log pO2) analyses. The closely matched in-plane bond lengths of the blocking and the active layers in these structures promote ionic compensation rather than electronic compensation upon aliovalent p-type doping. A comprehensive defect model that takes into account all the major defect species in an ionically compensated quadruple or quintuple perovskite provides a better means for understanding the electrical behavior of these novel materials. The presented model allows for the calculation of effective dopant and the oxygen interstitial concentrations in these materials.