Abstract
The solid solution LaSrNiO4-δ has been successfully prepared by a rapid method combining mechanical milling and heat treatment. The structure and microstructure transformations were characterized by X-ray powder diffraction, scanning and transmission electron microscopy. The dielectric property was also investigated. After 10 h of milling and 8 h of heat treatment at 1300 °C, X-ray diffraction analysis revealed LaSrNiO4-δ single phase, exhibiting tetragonal structure with space group of I4/mmm. This result was confirmed by using the ED pattern for sample using the [001] orientation. The corresponding lattice images show the compound to be well ordered, indicating the absence of stacking faults and the growth of the crystallites. Dielectric relaxation of charge-ordered LaSrNiO4-δceramic was investigated in the temperature range 100–450 K. Giant dielectric response was observed in this ceramic, and only one dielectric relaxation was found on the curve of the temperature dependence of dielectric constant. The thermal activated small polaronic hopping between two charge ordering temperatures should contribute to the giant dielectric response in the present ceramics.
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•LaSrNiO4-δ compound has been successfully prepared by mechanical milling for 10 h and heat treatment at 1300 °C for 8 h.•The X-ray diffraction analysis revealed LaSrNiO4-δ single phase, exhibiting tetragonal structure with space group of I4/mmm.•The ED pattern was used for sample using the [001] orientation and the corresponding lattice images show the compound to be well ordered.•Giant dielectric response was observed in the present ceramic, and only one dielectric relaxation was found on the curve of the temperature dependence of dielectric constant.