LAUSR

Abstract We present detailed magnetic properties of (1-x)BaTiO3–xCoFe2O4 (x = 1, 0.5, 0.4, 0.3, 0.2, 0.1, 0.75, 0.05, 0.025) nanocomposites, synthesized through multiple-step chemical synthesis technique. Stepwise synthesis and structural optimization of composites include oxalate route synthesis of BaTiO3 with specifically chosen tetragonality followed by mixing in citric acid solution, and a final addition of the precursor for CoFe2O4. Heat treatment temperature were appropriately chosen to obtain composites with distinct spinel and tetragonal perovskite phases. Peak broadening has been observed in composites being a consequence of presence of strain. Main goal of the present work is to investigate magnetic response as a function of temperature for various compositions and to compare them with the magnetic properties of CoFe2O4 nanoparticles. BaTiO3 acts as a barrier for the growth of the CoFe2O4 due to the phase separation between these constituent phases in the composites. The nanoscopic features are consistently observed in the magnetic properties of the composites. These features include increase in coercivity, stronger temperature dependence of coercivity and magnetic irreversibility. CoFe2O4 and BaTiO3 composites exhibit strong temperature dependence with a more than an order of magnitude increase in coercivity at low temperatures.