Annealing-dependent structural and magnetic properties of nickel oxide (NiO) nanoparticles in a silica matrix. Issue 14 (November 2015)

• Record Type: Journal Article
• Authors: Nikolić, Dobrica; Panjan, Matjaž; Blake, Graeme R.; Tadić, Marin
• Is Part Of: Journal of the European Ceramic Society. Volume 35:Issue 14(2015:Nov.)
• Page Start: 3843
• Page End: 3852
• Publication Date: 2015-11
• Subjects: Nickel oxide (NiO) -- Sol–gel combustion synthesis -- Interparticle interactions -- Superparamagnetism -- AC susceptibility; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2015.06.024
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: We show that annealing at high temperatures has a significant effect on the structural and magnetic properties of NiO/SiO2 nanostructures synthesized by a sol–gel combustion method. Samples underwent heat treatments at 500 °C, 800 °C, 950 °C and 1100 °C. As compared to the 500 °C sample, the 800 °C sample showed the following magnetic properties: much higher irreversibility temperature, a significantly broadened zero-field-cooled (ZFC) magnetization maximum, a decrease of the ZFC magnetization, an increase of the coercivity, and weaker inter-particle interactions. These changes can be attributed to agglomeration of nanoparticles in part of the sample. We believe that this agglomeration can be explained by the removal of thin regions of silica that separate nanoparticles in close proximity during the annealing process at 800 °C. Magnetic measurements for the 1100 sample reveal both an abrupt increase in size of the NiO nanoparticles, which is confirmed by TEM and XRPD measurements, and an increase in inter-particle interaction strength.