Abstract

The effect of La concentration on the kinetic character of the induced phase transition in PbMg_1/3Nb_2/3O₃–25PbTiO₃ ferroceramics is studied. Below the Vogel–Fulcher temperature, the time variations of the permittivity and optical transmittance in electric fields 0 < E < 6 kV/cm are analyzed. It was found that, in an electric field, in La-containing transparent ceramics, the permittivity and optical transmittance sharply decrease with time, which indicates an induced phase transition and an increase in the fraction of the ferroelectric phase. It is shown that, in La-undoped ceramics, the changes in the permittivity in the same fields are much smaller. It is found that the stability of the induced phase depends on the La concentration: the higher this concentration, the lower the stability. The results obtained are explained by both a varying degree of smearing of the phase transition and different sizes of polar regions, which depend on the La concentration.

中文翻译：

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镧浓度对PbMg 1/3 Nb 2/3 O 3 –25PbTiO 3透明陶瓷诱导相变动力学的影响

摘要

研究了镧浓度对PbMg _1/3 Nb _2/3 O ₃ –25PbTiO ₃铁陶瓷中诱导相变动力学特征的影响。在Vogel–Fulcher温度以下，电场0 < E时介电常数和光透射率的时间变化分析<6 kV / cm。已经发现，在电场中，在含La的透明陶瓷中，介电常数和光透射率随时间急剧下降，这表明感应的相变和铁电相的分数增加。结果表明，在未掺镧的陶瓷中，相同场中介电常数的变化要小得多。发现诱导相的稳定性取决于La浓度：该浓度越高，稳定性越低。所得结果通过相变拖尾的变化程度和极性区域的不同大小（取决于La浓度）来解释。