Ferrite

Literature References: A crystalline, usually man-made material, having a spinel structure and consisting essentially of ferric oxide and at least one other metallic oxide which is usually, although not always, divalent in nature. When molded into compressed bodies, the material is characterized by high magnetic permeability. Typified composition: Fe2O3 67-70%; ZnO 10-10.5%; MnO2 20-22.5%; CuO 0.1-10%; Co3O4 0.1%. Ferrites are prepd by ceramic techniques. The oxides or carbonates are milled in steel ball mills, and the mixture of very fine particles is dried and prefired in order to obtain a homogeneous end product: Hilpert, Ber. 42, 2248 (1909). Prepn: J. O. Simpkiss, US 2723238; R. L. Harvey, US 2723239 (both 1955 to RCA). Prepn of single crystals: Rooymans, Colloq. Int. Cent. Nat. Rech. Sci. No. 205, 151 (1972). Books: Snoek, New Developments in Ferromagnetic Materials (Elsevier, New York, 1947); Smit, Wijn, Ferrites (John Wiley, New York, 1959); Soohov, Theory and Applications of Ferrites (Prentice Hall, 1960); Standley, Oxide Magnetic Materials (Clarendon Press, Oxford, 1962); Ferrites, Proc. Int. Conf., Y. Hoshino et al., Eds. (University Park Press, Baltimore, 1971) 671 pp; E. E. Riches, Ferrites, A Review of Materials and Applications (Mills and Boon, London, 1972) 88 pp. Reviews with bibliographies: Gorter, Proc. IRE 43, 1945-1973 (1955); Fresh, "Methods of Preparation and Crystal Chemistry of Ferrites," ibid. 44, 1303-1311 (1956); Brailsford, Magnetic Materials (John Wiley, New York, 3rd ed., 1960) pp 160-181; Hogen, Sci. Am. 202, 92-104 (1960); Economos in Kirk-Othmer Encyclopedia of Chemical Technology vol. 8 (Interscience, New York, 2nd ed., 1965) pp 881-901; Gray, "Oxide Spinels" in High Temperature Oxides, Part IV, A. M. Alper, Ed. (Academic Press, New York, 1971) pp 77-107.