Crystal structure and electrical transport of nano-crystalline strontium-doped neodymium ortho-ferrites

Strontium-doped neodymium orthoferrites belong to the perovskite type of materials of a wide range of interests and applications. This material has an orthorhombic perovskite crystal system of space group (Pbnm) no. 62. Nd_0.6Sr_0.4FeO₃ is synthesized using the co-precipitation method, and the resulting precipitated powder was fired at different temperatures to control the nano-crystalline size. The effect of the nano-crystalline size on the structure and the electrical properties were studied. The EDS spectra confirmed that the compound was formed according to the suggested calculations. SEM micrographs showed the homogeneity of the nano grain size in the compound. The nano-crystalline size of the prepared samples, fired at 705 °C and at 850 °C were 40 nm and 90 nm, respectively. Nd_0.6Sr_0.4FeO₃ showed a semiconducting behavior according to the exponential dependence of resistivity on temperature in the range from 350 K up to 473 K. The temperature independence of impedance is found at high frequencies starting from 0.5 MHz. The frequency dependence–activation energy is found in the temperature range from 350 K up to 473 K. The found decrease in AC resistivity with frequency increase for Nd_0.6Sr_0.4FeO₃ showed that the hopping mechanism occurred in the charge carrier transfer. Graphical abstract Graphical abstract