Structural properties and electrical conduction mechanisms of Bi0.9Sm0.05Tb0.05FeO3 Thin Film

Bismuth ferrite BiFeO3 (BFO) is a fascinating multiferroic material, which exhibits strong magnetic and ferroelectric (FE) characteristics simultaneously at room temperature. The present work was aimed at the controlled growth of Bi0.9Sm0.05Tb0.05FeO3 (BSTFO) thin film prepared by hydrothermal method to enhance its magnetic moment as well as the electric properties. In this work, variation of electrical conduction with temperature is explained by employing few, relevant to perovskite oxide materials, conduction mechanisms. Variable-range hopping (VRH) and small-polaron hopping conduction mechanisms are used to analyze the conduction mechanism. Structure, ferromagnetic and dc electrical properties of Bi0.9Sm0.05Tb0.05FeO3thin films grown on SrTiO3 (100) substrates by hydrothermal method are reported. Saturation magnetization and room temperature resistivity values are found to be 160 emu/cm3 and 1.9 × 105 Ω m respectively. Raman spectroscopy study indicates anomalous changes of vibration modes around the Neel's temperature. The temperature dependent electrical resistivity shows two distinct regions suggesting two different conduction mechanisms which suggest that small polaron and variable-range-hopping conduction mechanisms are operative in 300-160 K and 160-90 K temperature regions respectively. The density of states, for our samples, at the Fermi level is found to be ∼1020 eV−1 cm−3.