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Abstract
An amorphous material based on multiferroic BiFeO3 was obtained, using melt quenching method. Its dielectric properties were studied within the temperature range −200 to 600°С. The material is characterized by a high dielectric permittivity ε ≈104 (at 200°С and a frequency of 100 Hz), due to the contribution of migration polarization. Using the DTA method, the glass transition temperature Tg ≈ 400°С and crystallization temperature Tcr ≈ 490°С were determined. It was found that the temperatures Tg and Tcr correspond to anomalies of ε, the superposition of which forms a diffuse maximum of the dielectric permittivity. Staged annealing leads to decrease of these anomalies and their shift along the temperature axis in opposite directions. Substantially below of Tg two thermally activated dielectric relaxation processes were revealed. The relaxation time of one of them is obeyed to the Arrhenius law with an activation energy U ≈ 0.53 eV and preexponential factor τ0 ≈ 4.38 10−12 s.