In the present investigation, La_0.75Ba_0.10Sr_0.15FeO_2.875-δ oxygen-deficient ferrites with δ = 0.00, 0.125 and 0.25 were synthesized by sol–gel method. The physical characterization has been carried out by X-ray diffraction, scanning electron microscope SEM, Raman spectroscopy, and complex impedance. All samples are formed in orthorhombic crystal symmetry with Pnma space group. Synthesized compounds have nanocrystallite size of 32–46 nm. Raman spectrum shows the oxygen vacancy effect on the tilt and stretching phonon modes. Electric properties were investigated in the framework of impedance and electric conductivity. The complex impedance was measured over a wide range of temperatures (300–380 K) and frequencies (40 Hz–1 MHz). The electrical measurements indicate semiconductor behavior for the three compositions and emphasize the evidence of contribution of grain boundaries in the transport properties. The ac conductivity curves obey the Jonsher universal power law and are assigned to hopping conduction mechanism. It is found that the values of activation energy, estimated from the conductivity analysis, are in the same order with those deduced from relaxation process. Such result proves that both processes, conduction and relaxation, are related to the same defect.

在本次调查中，香格里拉_0.75巴_0.10锶_0.15 FeO的_2.875-δ通过溶胶-凝胶法合成了δ= 0.00、0.125和0.25的缺氧铁氧体。物理表征已通过X射线衍射，扫描电子显微镜SEM，拉曼光谱和复阻抗进行。所有样品均以具有Pnma空间群的正交晶体对称性形成。合成的化合物具有32–46 nm的纳米微晶尺寸。拉曼光谱显示氧空位对倾斜和拉伸声子模式的影响。在阻抗和电导率的框架内研究了电性能。在很宽的温度（300–380 K）和频率（40 Hz–1 MHz）范围内测量了复阻抗。电学测量表明这三种成分的半导体行为，并强调了晶界对传输性质的贡献的证据。交流电导率曲线遵循Jonsher通用幂定律，并被分配给跳跃传导机制。发现，由电导率分析估计的活化能的值与由弛豫过程推导的那些值处于相同的顺序。这样的结果证明，传导和松弛这两个过程都与同一缺陷有关。