Cobalt magnetism

The real part is the magnetic permeability whereas the imaginary part is the magnetic loss. These losses are quite different from hysteresis or eddy current losses, because they are induced by domain wall and electron-spin resonance. These materials should be placed at position of magnetic field maxima for optimum absorption of microwave energy. For transition metal oxides such as iron, nickel, and cobalt magnetic losses are high. These powders can, therefore, be used as lossy impurities or additives to induce losses within solids for which dielectric loss is too small. 

Samarium (Sm), 74 631t, 634t electronic configuration, 1 41 At Samarium-cobalt magnets, 74 651 Sampatrilat, 5 159... 

In the early 1970 s when samarium-cobalt magnets were first being proposed as a replacement for platinum-cobalt in microwave tubes, few could have anticipated the success that was to follow. Notwithstanding the traumas brought about by a quadrupling of cobalt prices, their use has grown steadily to the point where they now command a vitally important position in the permanent magnet market. 

Phosphor manufacture is still a dominant factor for suppliers of rare earth chemicals. According to industry sources (29), approximately 1/3 of the monetary volume of rare earth chemicals is used by the electronics industry. Included in this figure is Sm O for samarium-cobalt magnets. The remainder includes Gd O, La.,0 and Tb 0, for x-ray and lighting phosphors, and Y O ana... 

The production of samarium cobalt magnets requires lhe use of calcium. The reaction is... 

Samarium cobalt magnets have three to six times greater magnetic energy than alnicn magnets. 

Poly(isoprene-fc- ferrocenyldimethyl- silane) M Cylinder Cobalt magnetic [153] media ... 

Paramagnetic currents on the atom in question. This allows for the fact that the electron cloud does not have spherical symmetry. This term is insignificant for H because the 2p and other states lie at such high energies, but is important in cobalt magnetic resonance. 

Platinum is also used in small amounts in alloys. For example, cobalt alloyed with platinum makes a powerful magnet. An alloy is made by melting and mixing two or more metals. The mixture has properties different from those of the individual metals. The platinum-cobalt magnet is one of the strongest magnets known. 

The application of 1,10-phenanthroline and principal-component regression procedure allows the determination of Cu in mixtures with Co and Fe [18]. The method was applied to the analysis of two cobalt magnetic alloys. 

Phenanthroline and extraction of the formed complex into 1,2-dichloroethane was used to determine iron in phosphate luminophores [5]. The method using 1,10-phenanthroline and FIA system has been described [6]. The use of 4,7-diphenyl-1,10-phenanthroline as chromogenic reagent allows simultaneous determination of iron (and ruthenium) as ternary complexes by extractive (1,2-dichloroethane) zero-order and second derivative spectrophotometry [7]. Iron (Co and Cu) in cobalt magnetic alloys were determined by using... 

Fig.l. The influence of 7 layers of barium stearate (curve b) in reducing the frictional coefficient between a cobalt magnetic tape and a recording head. Curve (a) is for an unprotected metal surface. (See Reference 8)... 

Cheng JY, Ross CA, Chan VZ-H, Thomas EL, Lammertink RGH, Vancso GJ (2001) Formation of a cobalt magnetic dot array via block copolymer lithography. Adv Mater 13 1174-1178... 

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