Samples of the system Li0.5+0.5xTixFe2.5-1.5xO4 (x = 0, 0.1, ..., 0.7) were prepared by the usual ceramic technique. IR absorption spectra were used for analysing the compositions. The AC conductivity <(sigma)over tilde (omega)> and dielectric properties (loss tangent tan delta, dielectric constant epsilon' and dielectric loss epsilon '') have been measured at various frequencies and temperatures. Three bands were observed in the IR spectra. The band at around 600 cm(-1) (nu(1)*) and another one at around 400 cm(-1) (nu(2)*) were assigned to the tetrahedral and octahedral complexes, respectively. A small band (nu(3)) at around 335 cm(-1) indicated the octahedral divalent metal-oxygen bond in these complexes. The threshold frequency for the electronic transition seems to increase with increasing Ti4+ content, namely with decreasing Fe3+ concentration. At room temperature (RT), the AC conductivity exhibits dispersion in the frequency range from 3 x 10(2) Hz to 5 x 10(5) Hz. The variation of tan delta with frequency at RT shows a peak in the range (2-6) x 10(5) Hz. The electrical conduction mechanism was explained in terms of the electron hopping model. Both effects (temperature and frequency) tend to increase epsilon' and epsilon ''. The composition dependence of the dielectric properties is divided into two regions. The first one is for x < 0.5 (for which long-range order is predominant) and the second one is for x greater than or equal to 0.5 (for which short-range order is predominant). [References: 29]
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机译：通过常规陶瓷技术制备系统Li0.5 + 0.5xTixFe2.5-1.5xO4（x = 0、0.1，...，0.7）的样品。 IR吸收光谱用于分析组成。已在各种频率和温度下测量了交流电导率<∑σ（Ω）和介电性能（正切损耗角正切，介电常数ε和介电损耗ε”）。在IR光谱中观察到三个带。大约600 cm（-1）（nu（1）*）和另一个大约400 cm（-1）（nu（2）*）的谱带分别分配给四面体和八面体复合体。约335 cm（-1）处的一条小条带（nu（3））表明这些络合物中存在八面体二价金属-氧键。电子跃迁的阈值频率似乎随着Ti4 +含量的增加而增加，即随着Fe3 +浓度的降低而增加。在室温（RT）下，AC电导率在3 x 10（2）Hz到5 x 10（5）Hz的频率范围内表现出色散。 tanδ随RT频率的变化在（2-6）x 10（5）Hz范围内显示一个峰值。用电子跳跃模型解释了导电机理。两种影响（温度和频率）都倾向于增加ε'和ε'。介电特性的成分依赖性分为两个区域。第一个是x <0.5（以长距离顺序为主），第二个是x大于或等于0.5（以短距离顺序为主）。 [参考：29]
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