Magnetic materials preparation

Abstract The focus of this chapter is primarily directed towards nanocrystalline soft magnetic materials prepared by crystallization of amorphous precursors. The key elements involved in the development of this class of materials are three-fold (i) theoretical models for magnetic softness in nanostructures (ii) nanostructure-property relationships and (iii) nanostructural formation mechanisms. This chapter surveys recent research on these three areas with emphasis placed on the principles underlying alloy design in soft magnetic nanostructures. 

Pirota KR, Navas D, Hernandez-Velez M, Nielsch K, Vasquez M (2004) Novel magnetic materials prepared by electrodeposition techniques arrays of nanowires and multi-layered microwires. J Alloy Compd 369 18-26... 

Coercivity of Thin-Film Media. The coercivity ia a magnetic material is an important parameter for appHcations but it is difficult to understand its physical background. It can be varied from nearly zero to more than 2000 kA/m ia a variety of materials. For thin-film recording media, values of more than 250 kA / m have been reported. First of all the coercivity is an extrinsic parameter and is strongly iafluenced by the microstmctural properties of the layer such as crystal size and shape, composition, and texture. These properties are directly related to the preparation conditions. Material choice and chemical inborn ogeneties are responsible for the Af of a material and this is also an influencing parameter of the final In crystalline material, the crystalline anisotropy field plays an important role. It is difficult to discriminate between all these parameters and to understand the coercivity origin ia the different thin-film materials ia detail. 

Geothite is produced by air oxidation of alkaline suspension of ferrous hydroxide (Sada etal., 1988). As a starting material for ferrous oxide, the preparation of fine particles with prescribed size, size distribution and shape is required in its application to magnetic materials for recording tapes and disks. With increasing oxidation rate, the crystal size decreases and the size distribution becomes sharper (Sada etal., 1988). The first step of the reaction. 

Haeiwa, T., Segawa, K. and Konishi, K. (2007) Magnetic properties of isolated Co nanopartides in Si02 capsule prepared with reversed micelle. Journal of Magnetism and Magnetic Materials,... 

Evans, D.G. and Duan X. (2006) Preparation of layered double hydroxides and their application as additives, polymers, as precursors to magnetic materials and in biology and... 

W. Giriat and J.K. Furdyna, Crystal Structure, Composition, and Materials Preparation of Diluted Magnetic Semiconductors... 

Pillai V, Kumar P, Hou M J, Ayyub P, Shah DO (1995) Preparation of Nanoparticles of Silver-Halides, Superconductors and Magnetic-Materials Using Water-in-Oil Microemulsions as Nano-Reactors. Adv Colloid Interface Sci 55 241-269... 

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