Impedance spectroscopy of V2O5–Bi2O3–BaTiO3 glass–ceramics

• The dielectric constant decreases from 10.4 × 102 to 2.68 × 102 with increasing BaTiO3.
• Nanocrystals BaTi4O9 and Ba3TiV4O15 embedded in the present glass ceramic matrix.
• Incorporation of nanocrystallites particles BaTi4O9 into present glasses leads to increasing the dielectric constant.
• The high dielectric constant these glass ceramic indicates the possibility of their use as capacitor material.

The glasses within composition as: (80 − x)V2O5/20Bi2O3/xBaTiO3 with x = 2.5, 5, 7.5 and 10 mol% have been prepared. The glass transition (Tg) increases with increasing BaTiO3 content. Synthesized glasses ceramic containing BaTi4O9, Ba3TiV4O15 nanoparticles of the order of 25–35 nm and 30–46 nm, respectively were estimated using XRD. The dielectric properties over wide ranges of frequencies and temperatures were investigated as a function of BaTiO3 content by impedance spectroscopy measurements. The hopping frequency, ωh, dielectric constant, ε′, activation energies for the DC conduction, Eσ, the relaxation process, Ec, and stretched exponential parameter β of the glasses samples have been estimated. The, ωh,β, decrease from 51.63 to 0.31 × 106 (s−1), 0.84 to 0.79 with increasing BaTiO3 respectively. Otherwise, the Eσ, increase from 0.279 to 0.306 eV with increasing BaTiO3. The value of dielectric constant equal 9.5·103 for the 2.5BaTiO3/77.5V2O5/20Bi2O3 glasses-ceramic at 330 K for 1 KHz which is ten times larger than that of same glasses composition. Finally the relaxation properties of the investigated glasses are presented in the electric modulus formalism, where the relaxation time and the respective activation energy were determined.

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