Preparation and electrical properties of inorganic electride [Y2Ti2O6]2+(2e-).

ABSTRACT

Oxygen-depleted samples [Y2Ti2O7-x ]2x+(2xe-) (0 ≤ x ≤ 1.0) were prepared by reducing Y2TiO7 powders at 500 °C to 650 °C using CaH2 as a reductive agent, where x represents the content of , which was determined by thermogravimetric analysis. Powder X-ray diffraction patterns illustrate that the pure pyrochlore phase is kept for the samples with x ≤ 1.0, whereas the apparent x values surpass 1.0, and the impurity phase Y2O3 appears. The electride [Y2Ti2O7-x ]2x+(2xe-) (x ≈ 1.0) can be obtained under a reductive condition, in which the concentration of VO is 7.75 × 1021 cm-3. The electron paramagnetic resonance measurements gave the concentration of unpaired electrons in the electride as 1.30 × 1021 cm-3, indicating that the degree of the ionization of is less than 10%. Conductivity measurements for a sintered pellet sample (relative density ∼ 70%) indicate that the electride has quite high conductivity (∼1.09 S cm-1 at 300 K). The conduction was interpreted by using the variable range hopping mechanisms.