Investigation of structural and dielectric behavior of Eu2(B′0.5 B″0.5)2O7 (B′ = Ba; B″ = W, Mo) ceramics

Defect pyrochlore-type Eu2(B′0.5 B″0.5)2O7 (B′ = Ba; B″ = W, Mo) oxides ceramics were prepared by using high-temperature solid-state reaction technique. Preliminary studies of X-ray diffraction (XRD) patterns of the compounds at room temperature suggested that compounds have single phase orthorhombic structures. Studies of dielectric properties (dielectric constant (ɛ) and tangent loss (tan δ)) both as a function of frequency (4 kHz to 1 MHz) and temperatures (30–344 °C) does not exhibit dielectric anomaly. The Cole–Cole plot confirms the polydispersive nature of dielectric relaxation of Eu2(Ba0.5W0.5)2O7 (EBW) and Eu2(Ba0.5Mo0.5)2O7 (EBM) compounds. Variation of dc resistivity with temperature (94–315 °C) at a constant electric field of 60 V/cm exhibits the semiconductor characteristics of the material.

Research highlights▶ Defect pyrochlore-type Eu2(B′0.5 B″0.5)2O7 (B′ = Ba; B″ = W, Mo) oxides ceramics were prepared by using high-temperature solid-state reaction technique. Preliminary studies of X-ray diffraction (XRD) patterns of the compounds at room temperature suggested that compounds have single phase orthorhombic structures. Studies of the dielectric measurements of the compound as a function of frequency (4 kHz to 1 MHz) at room temperature and temperature (30–344 °C) at 20 and 100 kHz suggest that the compound do not have dielectric anomaly within this frequency and temperature ranges. The Cole–Cole plot confirms the polydispersive nature of dielectric relaxation of Eu2(Ba0.5W0.5)2O7 (EBW) and Eu2(Ba0.5Mo0.5)2O7 (EBM) compounds. Variation of dc resistivity with temperature (94–315 °C) at a constant electric field of 60 V/cm exhibits the semiconductor characteristics of the material.