Influence of Mg-substitution on structural and electrical properties of ion-conducting Ca-doped tri-yttrium gallate

Abstract

The signature of oxide ion conductivity was perceived in acceptor-doped (alkaline-earth metals) Y3GaO6. An acceptor doping of 2%Ca in Y3GaO6 (i.e., Y2.94Ca0.06GaO6) has been found to exhibit a remarkable conductivity. The present work examines the conductivity behavior of 2% Ca-doped tri-yttrium gallate (Y2.94Ca0.06GaO6) and also the effect of Mg-substitution on the phase formation and electrical conductivity of Y2.94Ca0.06GaO6 for its possible application as a solid electrolyte. Polycrystalline dense ceramic samples of Y2.94Ca0.06Ga1−xMgxO6−δ (with x =.00–.04) were fabricated using the conventional solid-state reaction route. The X-ray diffraction patterns were recorded to confirm the phase formation. The solid solubility limit of Mg2+ at Ga3+ site was found for x <.03. All the samples were observed to exhibit orthorhombic structure with Cmc21 symmetry (ICSD no.: 155086). Scanning electron microscopy (SEM) morphology reveals dense polygonal grains with vibrant grain boundaries. A significant increase in the conductivity is observed by substituting 1 mol% of Mg2+ at the Ga3+ site of Y2.94Ca0.06Ga1−xMgxO6−δ. However, a further addition of higher dopant concentration of Mg2+ leads to a decline in the electrical conductivity. A relationship between the dopant concentration, phase formation, and structural characterizations has been established to analyze the conductivity behavior. © 2022 The American Ceramic Society.