Magnetite magnetic properties

With respect to magnetic properties, the intrinsic magnetic susceptibiHty of pure chrysotile is very weak. However, the presence of associated minerals such as magnetite, as weU as substitution ions (Fe, Mn), increases the magnetic susceptibiHty to values around 6 x 10 m /kg. With amphiboles, the magnetic susceptibiHty is much higher, mainly because of the high iron content typically, amosite and crocidoHte exhibit susceptibiHty values of 100 and 75 X 10 m /kg, respectively (23). 

The sensitive dependence of the electrical and magnetic properties of spinel-type compounds on composition, temperature, and detailed cation arrangement has proved a powerful incentive for the extensive study of these compounds in connection with the solid-state electronics industry. Perhaps the best-known examples are the ferrites, including the extraordinary compound magnetite Fc304 (p. 1080) which has an inverse spinel structure (Fe )t[Fe Fe ]o04. 

Zhao, S. and Asuha, S. (2010) One-pot synthesis of magnetite nanopowders and their magnetic properties. Powder Technology, 197 (3), 295-297. 

Micro- and nanobeads with magnetic properties have recently become popular since these tools can be manipulated, e.g., collected in the region of interest. Magnetite nanoparticles are introduced in order to render the polymeric beads magnetic. Preparation and application of magnetic beads will be discussed in more detail in Sect 5.5. 

Precipitation was found to be a very useful method for preparation of nanobeads with magnetic properties [17] since not only indicators but also small lipophilic magnetite nanobeads (having diameter of a few nanometers) can be incorporated inside the polymeric beads. Such multifunctional magnetic beads can be guided to the region of interest, be collected and manipulated there. 

Eggar-Gibbs ZG, Jude B, Dominik J, Loizeau JL, Oldfield F (1999) Possible evidence for dissimilatory bacterial magnetite dominating the magnetic properties of recent lake sediments. Earth Planet Sci Lett 168 1-6... 

The industrial dust deposited in the metropolitan area of Shanghai consisted of high-coercivity (hematite) and low-coercivity (magnetite/maghemite) particles, usually < 10 pm in size. Four different dust sources could be distinguished on the basis of magnetic properties (Shu et al. 2000). Given previously reported links between... 

Aliev, F.G. Correa Duarte, M.A. Mamedov, A. Ostrander, J.W. Giersig, M. Liz-Marjan, L.M. Kotov, N.A. (1999) Layer-by-layer assembly of core shell magnetite nanoparticles Effect of silica coating on interparticle interactions and magnetic properties. Adv. Mater. 11 1006-1010... 

The mineral magnetite may be characterized from its physical and magnetic properties and by x-ray methods. The iron content in the oxide may be determined by AA, ICP/AES, x-ray fluorescence and other instrumental techniques (See Iron). 

Lodestone, also known as magnetite, was one of the first known magnetic materials. Its ability to attract iron was known as far back as 600 B.C., and it was used in compasses beginning in the thirteenth century. It was studies by I. L. Snoeck at the Philips Laboratories in Holland in the 1940s, however, that led to the first application of oxide ceramics with strong magnetic properties. 

The confinement of two species in stoichiometric amounts within the nanodroplets also allows the synthesis of mixed species. A mixture of Fe2+ and Fe3+ salts leads to the formation of magnetite, Fe304. The final dispersion with a particle size of 200 nm is black and shows magnetic properties. As is seen in the TEM pictures (Fig. 23b), the superstructure composed of 10-nm nanoparticles as determined by WAXS is anisotropic (lemon shaped), and constituting needle shaped nanocrystals, can be identified inside the particles, arranged as bundles along the main axis of the lemons . 

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