Effect of microwave sintering on microstructural and magnetic properties of strontium hexaferrite using sol–gel technique S. Kanagesan • M. Hashim • S. Jesurani • T. Kalaivani • I. Ismail • C. S. Ahmod Received: 2 March 2013 / Accepted: 4 June 2013 / Published online: 14 June 2013 Ó Springer Science+Business Media New York 2013 Abstract The sol–gel method is used to prepared hexa- ferrite using D-Fructose as a fuel. The effect of sintering temperature on the microstructure of SrFe 12 O 19 ceramics is analyzed. The observed XRD results indicate a well- formed crystalline phase of dense hexagonal SrFe 12 O 19 ceramics. From this analysis, no secondary phases are identified. The microstructure of the sintered single phase M-type ferrites ceramics displays a hexagonal-platelet like morphology. Sintering temperature can markedly affect the grains in sintered ferrite. The sintered product is shown to be dense microstructure with relatively small grains. The maximum sintered density 95 % was obtained at lower temperature of 1,150 °C. In addition, saturation magneti- zation (50.43 emu/g) and the coercivity (H c ) 5,594.53 Gauss were observed. 1 Introduction Recently, Ba and Sr M-type inorganic hexaferrites have attracted much attention because of their special properties [1, 2]. Among the inorganic magnetic particles, SrFe 12 O 19 – SrF had received great attention because of their high coercivity, which originates from high magneto crystalline anisotropy with single easy magnetization axis. It has been recognized that it can be used as permanent magnets, recording media, telecommunication, components in microwave devices [3] and has the following advantages: the raw material for strontium ferrite is abundant; the manufacturing cost is low; its properties are stable; and the problem of oxidation of the product is avoided. The properties of this magnetic material are related to purity, size, and morphology of the powder, by modifying its microstructure and by controlling its chemical composi- tion, size, morphology and heat treatment. Kloubek et al. [4] reported modified properties of SrF. In particular, strontium hexaferrites are used for their hard magnetic properties. The importance of these materials can be explained by their low price and their reasonable magnetic performances, so the wide range of applications like elec- tric motors, loudspeaker and toys. To produce magnets with large remanence and coercivity, it is essential to go for ceramic process which in turn controls the complex interplay between a dense microstructure and grain growth. Ferrite powder particles should have dimen- sions below 1 lm to allow some unavoidable grain growth during sintering and to limit the grain size in the sintered magnets to a few microns. Sub-micron powders may be improved by calcination procedures which allow the prep- aration of high-performance magnets with large remanence [5]. However, this design fundamentally does not account for the interaction between the processing parameters. In view of cost and time saving [6] the size of the particles can be controlled during preparation, depending on the production method, or after preparation, by mechanical [7] thermal treatments [8]. However, homogeneous strontium hexaferrite S. Kanagesan (&) Á M. Hashim Á I. Ismail Á C. S. Ahmod Materials Synthesis and Characterization Laboratory (MSCL), Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia e-mail: kanagu1980@gmail.com S. Jesurani Department of Physics, Jeyaraj Annapackium College for Women, Periyakulam 625601, Tamil Nadu, India T. Kalaivani Department of Physics, Center for Material Science and Nano Devices, SRM University, Kattankulathur 603 203, Tamil Nadu, India 123 J Mater Sci: Mater Electron (2013) 24:3881–3884 DOI 10.1007/s10854-013-1333-9