Magnetite morphology

For all three types of anisotropy the coercivity can be calculated (Tab. 7.7). For SD magnetite and maghemite, shape anisotropy, dominates over strain and crystal anisotropy, whereas for hematite and goethite, morphology has little influence on coer-civity. 

Heat synthetic lepidocrocite or magnetite in air (in a furnace) at 250 °C for 2 hr or 5 hr, respectively. The product will have the morphology of the precursor. 

Blesa, M. (1994) Morphological properties of a-FeOOH, y-FeOOH and Fej04 obtained by oxidation of aqueous Fe(II) solutions. J. Colloid Interface Sd. 165 244-252 Dong, H. Fredrickson, J.K. Kennedy, D.W. Za-chara, J.M. Kukkadapu, R.K. Onstott,T.C. (2000) Mineral transformations associated with the microbial reduction of magnetite. Chem. Geol. 169 299-318 Donnay J.D.H. Marker, D. (1935) A new law... 

Maroto, A.J.G. (1981) Some observations on the composition and morphology of synthetic magnetites obtained by different routes. J. inorg. nucl. Chem. 43 1489-1493... 

As summarized in Table 14.1, teeth, bones, shells, etc. are indispensable components, consisting of inorganic mineral crystals and protein film, with sizes, morphologies, and textures suitable to fulfil the function of the particular organs involved. In this section we will look at hydroxyapatite, aragonite and calcite (two polymorphs of CaCO ), and magnetite in greater detail. 

When iron catalysts are exposed to FT synthesis reaction environments, the catalysts first transform from hematite into magnetite. The transformation into magnetite is rapid and occurs pseudomorphically where the shape of the hematite crystals is retained including their swiss-cheese morphology. The transformation from magnetite to carbide is slow and is affected... 

Mann S. (1985) Structure, morphology, and crystal growth of bacterial magnetite. In Magnetite Biomineralization and Magnetoreception in Organisms (eds. J. L. Kirschvink, D. S. Jones, and B. J. MacEadden). Plenum, New York, pp. 311-332. 

Masuda, T., Endo, J., Osakabe, N., Tonomura, A., and Arii, T., Morphology and structure of biogenic magnetite particles. Nature, 302, 411, 1983. 

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