Structural and electrical properties of nanostructured fluorite-like R2 + x TiO5 + 1.5x (R = Y, Er; 0 ≤ x ≤ 1)

We have studied the detailed structure and electrical properties of single-crystal and polycrystalline fluorite-like R2 + x TiO5 + 1.5x (R = Y, Er; 0 ? x ? 1) materials and found the first evidence for the formation of nanodomains ? 40a1000 nm in size, which are coherent with the matrix and have various degrees of structural order. The formation of the nanodomains is driven by internal stress. Using impedance spectroscopy, we have determined the electrical conductivity of the materials in air at temperatures from 300 to 1000ADGC. The 1000ADGC electrical conductivity of Y2TiO5 (Er2TiO5) and Y2.44TiO5.67 (Er2.44TiO5.67) is 1.86 A 10?3 (1.35 A 10?3) and 9.98 A 10?4 (8.13 A 10?4) S/cm, respectively. The effective activation energy for electrical conduction in Y2TiO5 (Er2TiO5) and Y2.44TiO5.67 (Er2.44TiO5.67) is 1.16 (1.21) and 1.25 (1.21) eV, respectively.