Magnetism basic concepts

Concluding this section, two interesting variants of the STM should be addressed. The spin-polarized STM (SPSTM), which works with a ferromagnetic tip, can be used to probe surface magnetism with high resolution [5.47, 5.48]. Other modifications of the STM involve electromagnetic radiation, whereby two basic concepts can... 

At the beginning of this century slow magnetic relaxation in the paramagnetic phase of a ID system was reported for a Co2+ nitronyl-nitroxide chain [58]. The dynamics was under many respects very similar to that of SMMs and these ID systems were later named SCM to underline the analogies [9]. Since then an intense research activity, though not as spread out as for SMMs, has been devoted to SCMs. The interested reader can find extensive literature on the subject, including exhaustive reviews and a book chapter [59-63]. The aim here is to provide some basic concepts of the phenomenon and to introduce some selected examples of SCMs based on lanthanide ions. 

The first four chapters introduce basic concepts that are developed to build up a framework for understanding defect chemistry and physics. Thereafter, chapters focus rather more on properties related to applications. Chapter 5 describes diffusion in solids Chapter 6, ionic conductivity Chapters 7 and 8 the important topics of electronic conductivity, both intrinsic (Chapter 7) and extrinsic (Chapter 8). The final chapter gives a selected account of magnetic and optical defects. 

On a smaller scale many new functional polymers are produced having valuable properties for electrical, optical or magnetic applications. There exist numerous metal catalysed processes and we will discuss only a few to explain basic concepts using both examples from bulk polymers and fine chemical, high-value polymers. 

A short exposition of the basic concepts of actinide magnetic research and of the different aspects of magnetic ordering in actinide solids is followed by a discussion of experimental and interpretational aspects, in particular the difficulty always encountered of separating the different contributions. 

This chapter is intended to recall the principles of magnetism, the definition of magnetic induction and of magnetic induction in a vacuum which is referred to as magnetic field. Readers may not recollect that the molar magnetic susceptibility is expressed in cubic meters per mol Some properties of electron and nuclear spins are reviewed and finally some basic concepts of the magnetic resonance experiments are refreshed. In summary, this chapter should introduce the readers into the language used by the authors. 

This chapter gives an introduction to the basic concepts of magnetism in organic paramagnetic soft matter materials. Key concepts are emphasized using example case studies. Detailed analysis covers radicals functionalized with phenols and with benzimidazole functionalities, which induce various degrees of crystal self-assembly, depending on specific structures. A review with over 200 references and notes. 

This is the basic concept of Magic Angle Spinning NMR the sample is placed in a rotor, spinning at high speed around an axis at 54,7° to the axis of the applied magnetic field. 

The basic concept of micromagnetism is to replace the atomic magnetic moments by a continuous function of position. In a continuum theory the local direction of the magnetic moments may be described by the magnetic polarization vector... 

This chapter introduces the basic concepts that are needed to understand the quantum phenomena observed in molecular nanomagnets. All tunneling studies presented here were performed by magnetization measurements on single crystals using an array of micro-SQUIDs [4]. 

Chapter 1 is an introduction into some basic concepts of interest to more than one chapter, such as the definitions of basic magnetic quantities. Chapters 2-4 are devoted to the theory of magnetic nanostructures, 5 deals with the characterization of the structures, and 6-10 are devoted to specific systems. Applications of advanced magnetic nanostructures are discussed in 11-15 and, finally, the appendix lists and briefly discusses magnetic properties of typical starting materials. 

Wilson M. A. (1989) Solid-state nuclear magnetic resonance spectroscopy of humic substances basic concepts and techniques. In Humic Substances II in Search of Structure (eds. M. H. B. Hayes, P. MacCarthy, R. L. Malcolm, and M. J. Swift). Wiley, pp. 309-338. 

Two parts of molecules have magnetic properties, nuclei and electrons. The magnetism of nuclei gives rise to nuclear magnetic resonance spectroscopy (NMR) although there is much similarity between the basic concepts of ESR and NMR, there are differences in the spectrometers used and their applications. 

The electron Hamiltonian (15) describes the so-called orbital exchange coupling in a three-dimensional (3D) crystal lattice. The Pauli matrices, cr O ), have the same properties as the z-component spin operator with S = As a i) represents not a real spin but orbital motion of electrons, it is called pseudo spin. For the respective solid-state 3D-exchange problem, basic concepts and approximations were well developed in physics of magnetic phase transitions. The key approach is the mean-fleld approximation. Similar to (8), it is based on the assumption that fluctuations, s(i) = terms quadratic in s i) can be neglected. We do not go into details here because the respective solution is well-known and discussed in many basic texts of solid state physics (e.g., see [15]). 

But rather than considering spatially-dependent spectral properties, which often are essential for image contrast, time-dependent gradients shall be admitted to illustrate the basic concepts of space encoding. Then the space-dependent magnetization phase - yGrf in the exponent of the integrand has to be replaced by... 

Having understood basic concepts like voltseconds, current components, worst-case voltage, and also how to do an initial (quick) selection of an off-the-shelf inductor, we will now try to go inside the magnetic component, so as to learn what happens in terms of the magnetic fields present inside its core. We will then use this information to do a more complete validation of a selected off-the-shelf inductor. Then we will find the remaining (worst-case) stresses of the converter. 

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