Ceramic magnetic properties

Wu R and Freeman A J 1994 Magnetism at metal-ceramic interfaces effects of a Au overlayer on the magnetic properties of Fe/MgO(001) J. Magn. Magn. Mater. 137 127-33... 

The magnetic properties of ferrites are intricately related to composition, microstmcture, and processing much more so than in the case of metals primarily because of the complex chemistry of the oxides and because of the ceramic processing requited to produce the finished parts. 

As well documented in the literature, spinels are basically known for its magnetic properties. Generally, high temperature preparation methods (ceramic methods) have... 

Below is a brief review of the published calculations of yttrium ceramics based on the ECM approach. In studies by Goodman et al. [20] and Kaplan et al. [25,26], the embedded quantum clusters, representing the YBa2Cu307 x ceramics (with different x), were calculated by the discrete variation method in the local density approximation (EDA). Although in these studies many interesting results were obtained, it is necessary to keep in mind that the EDA approach has a restricted applicability to cuprate oxides, e.g. it does not describe correctly the magnetic properties [41] and gives an inadequate description of anisotropic effects [42,43]. Therefore, comparative ab initio calculations in the frame of the Hartree-Fock approximation are desirable. 

Most of the important magnetic ceramics are of the ferrimagnetic class. However, some ceramics do exhibit other types of magnetic behavior. These ceramic materials will be described first, followed by a more thorough description of an important class of ferrimagnetic ceramics called ferrites. Finally, a topic related to the magnetic properties of ceramic superconductors will be introduced. 

Table 6.21 Selected Magnetic Properties of Some Antiferromagnetic Ceramics...

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 previous section showed that the physical properties of the carbides and nitrides differed substantially from those of the parent metals, and resembled those of ceramic compounds. The electronic and magnetic properties of the carbides and nitrides provide an interesting contrast, because here there are similarities with the metals. 

Dielectrics, optics and magnetism (properties of certain ceramic materials)... 

The initial interest in ceramic matrix nanocomposites arose from reports by Niihara and co-workers indicating enhanced mechanical properties due to the presence of ceramic (SiC) particles.53 With the development of various processing routes to introduce nanometer-sized metal particles in a ceramic matrix, variations in functional (i.e. magnetic) properties are possible. In the following we briefly review the microstructurally dependent properties, with emphasis on the possible mechanisms leading to improved properties and using SiC-reinforced alumina as a point of comparison. 

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