Magnetic materials physical structure

We discuss briefly some basic topics in materials physics such as crystallography, lattice vibrations, band structure, x-ray diffraction, dielectric relaxation, nuclear magnetic resonance and Mossbauer effects in this chapter. These topics are an important part of the core of this book. Therefore, an initial analysis of these topics is useful, especially for those readers who do not have a solid background in materials physics, to understand some of the different problems that are examined later in the rest of the book. 

In the past decades, nuclear magnetic resonance (NMR) spectroscopy has been used extensively to study various aspects of polymer chemistry and engineering. Fig. 1 shows the relationship among polymerization conditions, polymer structure, and the material s physical structure and end uses. Solution, solid state, and imaging NMR techniques contribute to imderstanding the physical and chemical aspects of the route from raw materials to final product. Solution NMR provides information about all aspects of the polymerization reactions and the final structure of the synthesized polymer. This information can be correlated with the material s final properties and provide feedback to control the initial polymerization process so that the fraction of structures responsible for desirable properties can be controlled in a systematic way. 

Many of the industrial applications of materials make use of their particular electronic and magnetic properties. These properties are often directly related to their physical structure. Since the atoms/ions in the extended structure of these materials are very close together, the interactions between them occur throughout the lattice. 

Krishnan, R., Lassri, H. Rougier, P. (1987). Magnetic properties of amorphous FeErBSi ribbons. Journal of Applied Physics, 62, 3463-4. Krishnan, R., Porte, M., Tessier, M. Flevaris, N. K. (1991). Structural and magnetic studies in Co-Pt multilayers. In Science and Technology of Nanostructured Magnetic Materials. Eds. G. C. Hadjipanayis and G. A. 

It is an understatement to say that the manipulation of nuclear magnetization in physical and spin space described in the three chapters of this section on NMR constitute one of the most powerful spectroscopic approaches to the study of matter in solution and solid phases. NMR continues to evolve in delightful ways that keeps this spectroscopy fresh and applicable in solving structure and dynamics problems in complex materials. 

Since most of magnetic materials are metal or metal oxides, the raw material is straightforward and can be easily found. However, the technology difficulties remain in the purity section. As mentioned above, the different chemical properties are based on the structure and the concentration of the alloys, so the synthesis process has to be controlled very carefiilly. Furthermore, when it comes to the nanoscale, many of the classic physics laws are not applicable and quantum physics is required. The synthesis of ferrofluid consists of synthetic procedures. Basically, it is the thermal decomposition of metal organic compounds or the thermal decomposition of monometallic metal organic compounds. Figure 1.1 shows examples of magnetic nanoparticles for one simple structure and for metal alloy compounds. 

In general, one can insert one or more types of fillers in polymeric matrices aiming for a unique combination of properties, and these fillers may present diflerent chemical and physical properties, and also broad dimensional range these fillers can present no dimension (i.e. nanoparticles), be unidimensional (nanotubes), bidimensional (coatings and lamers) or tridimensional (tridimensional nets or macroparticles). " The inclusion of these fillers in vulcanized NR, generating composite or nanocomposite materials, gives to these materials different structural, chemical, physical, thermal, electric, electrochemical, optical and magnetic properties. ... 

Part 5 covers special structures such as liquid crystals, solid surfaces and mesoscopic and nanostructured materials. The chapter on liquid crystals covers physical properties of the most common liquid crystalline substances as well as some liquid crystalline mixtures. Data compiled in the chapter on solid surfaces refer to atomically clean and well characterized surfaces. The values reported are mainly averages from different authors where reference to the original papers is made. In the chapter on nanostructured materials emphasis is placed on size and confinement effects. The properties associated with electronic confinement are addressed and particular attention is drawn to semiconductor-doped matrices. The two main applications of nanostructured magnetic materials, spintronics and ultrahigh-density data storage media, are also treated. 

Atomic force microscopes (AFM), whose tips are typically made of silicon or diamond, can probe sur-laces made of practically any material. As the tip of an atomic force microscope is dragged across the sur-lace of a specimen, it is either deflected by or drawn toward the object, depending on whether the atoms in the object are repelled by or attracted to the microscope s tip. By measuring these forces, a magnified representation of the physical structure of the sample can be created. By changing the modes in which these microscopes operate, different properties such as magnetism, friction, and electrical conductivity can be assessed. 

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