Microstructure effects on the local order and electronic defects in (Al, Ti, Mg) co-doped ZnO conductive ceramics

Abstract Fine particles with different sizes of (Al, Ti, Mg) oxide co-doped ZnO ceramics were realized by a suitable grinding and a mechanical ball milling, respectively. The investigations were devoted to understand the origin of the electrical conductivity evolution with the microstructure by analyzing the local order and defect involvement in the crystalline sites of ZnO ceramics. Experimental investigations of particles were conducted to probe the local order and electronic defects with an emphasis on the electrical behavior of ceramics. Particularly, Al doping is intimately correlated with the high conductivity induced from the stabilization of particular AlZn-Zni complexes. The conduction electrons are probed through the induced Knight Shift on NMR spectra and also from the particular relaxation mechanisms of paramagnetic centers revealed by EPR studies. The correlation between the electronic active defects, the microstructure in small sized particles of ZnO based ceramics and the electrical behavior are pointed out and discussed.