Iron ferrite magnetic properties

Spinel ferrites, isostmctural with the mineral spinel [1302-67-6] MgAl204, combine interesting soft magnetic properties with a relatively high electrical resistivity. The latter permits low eddy current losses in a-c appHcations, and based on this feature spinel ferrites have largely replaced the iron-based core materials in the r-f range. The main representatives are MnZn-ferrites (frequencies up to about 1 MH2) and NiZn-ferrites (frequencies 1 MHz). 

Magnetic properties Barium ferrite, iron oxide Ba, Fe... 

Hydrothermal Method. Iron [Fe(III)], barium, and the dopants are precipitated as their hydroxides and reacted with an excess of sodium hydroxide solution (up to 6 mol/L) at 250-350 °C in an autoclave. This is generally followed by an annealing treatment at 750-800°C to obtain products with the desired magnetic properties. Many variations of the process have been described [5.36]-[5.40], the earliest report being from 1969 [5.41], In later processes, hydrothermal synthesis is followed by coating with cubic ferrites, a process resembling the cobalt modification of iron oxides (see Section 5.1.2). The object is to increase the saturation magnetization of the material [5.42]-[5.44],... 

Hilpert, S. (1909) The structures and origins of the magnetic properties of ferrites and iron oxide, Ber. Deutsch. Chem. Ges., 42, 2248-61. 

Metselaar, R. Huyberts, M. A. H. (1973). The stoichiometry and defect structure of yttrium iron garnet and the nature of the centres active in the photomagnetic effect. Journal of Physics and Chemistry of Solids, 34,2257-63. Miyahara, S. Ohnishi, H. (1956). Cation arrangement and magnetic properties of copper ferrite-chromite series. Journal of the Physical Society, Japan, 11, 1296-7. 

Magnetic properties have also been induced into polysiloxanes by incorporation of particles of a ferrite,2 - 266- 267 iron,2 269 or magnetite.22 - 271 ihese materials can show large field-induced elongations,2 ... 

Glass-ceramics, having ferrimagnetic properties, were developed by Le Bras (1976). The magnetic property was achieved on the basis of the precipitation of calcium ferrite in glasses. Therefore, iron oxides were incorporated into silicate glasses. The base glass was characterized by the composition in ... 

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