Characterization of columbite ceramics A1–xNb2O6 by positron annihilation spectroscopy

Abstract Columbite ceramics A 1–x Nb 2 O 6 (where A = Mg, Co, Zn and x = 0, ‐0.005, ‐0.01, ‐0.03, ‐0.04) were studied by means of positron annihilation spectroscopy. The lifetime spectra revealed the presence of two lifetime components. The first component originates from positron annihilation inside of the grains. The second component is due to annihilations in the grain boundary regions. From the intensity of the second component and …