pH control of magnetic properties in precipitation-hydrothermal-derived CoFe2O4

• Published in: Journal of alloys and compounds Vol. 589; pp. 271 - 277
• Main Authors: Jovanović, Sonja, Spreitzer, Matjaž, Otoničar, Mojca, Jeon, Jae-Ho, Suvorov, Danilo
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.03.2014; Elsevier
• Subjects: Chemical synthesis; Chemical synthesis methods; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetic measurements; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetization; Materials science; Methods of nanofabrication; Nanostructured materials; Physics; Magnetic measurements; Magnetization; Chemical synthesis; Nanostructured materials; Crystallization; pH effect; Fabrication property relation; Nanoparticles; Cobalt Iron Oxides Mixed; Precipitation; Hydrothermal synthesis; Coercive force; Microstructure; Nanomaterial synthesis
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.11.217

•Formation of CoFe2O4 precipitate at constant pH=13.1.•Post-precipitation adjustment of pH and subsequent hydrothermal treatment.•The conditions: pH, temperature and synthesis time were systematically varied.•At pH>6.2 the average crystallite size increases linearly with the pH value.•By controlling pH the magnetic properties of CoFe2O4 can be tuned. Cobalt ferrite nanoparticles (CFO NPs) were synthesized using precipitation followed by a hydrothermal treatment. The conditions for precipitation were kept constant, while the pH, the temperature and the synthesis time for the hydrothermal treatment were systematically varied. The results show that the pH plays the dominant role in the formation, growth and crystallization of the desired phase. Furthermore, by controlling the pH the magnetic properties, such as the magnetization and the coercivity of the CFO NPs, can be tuned. An increase in the temperature induced both particle growth and a change of the morphology. The variation of the synthesis time indicated that the hydrothermal reaction proceeds for up to 8h; however, a further prolongation of the synthesis time does not affect the structural and magnetic properties to any significant extent.