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Elementary dipole

The partial orientation of the elementary dipoles in a paramagnetic solid is counteracted by thermal agitation, and it would be expected that at high temperatures the random motion of the atoms in the solid would cancel the alignment due to the magnetic field. The paramagnetic susceptibility would therefore be expected to vary with temperature. The temperature dependence is given by the Curie law ... [Pg.400]

The partial orientation of the elementary dipoles in a paramagnetic solid is counteracted by thermal agitation, and it would be expected that at high temperatures... [Pg.490]

Classical relaxors [22,23] are perovskite soUd solutions like PbMgi/3Nb2/303 (PMN), which exhibit both site and charge disorder resulting in random fields in addition to random bonds. In contrast to dipolar glasses where the elementary dipole moments exist on the atomic scale, the relaxor state is characterized by the presence of polar clusters of nanometric size. The dynamical properties of relaxor ferroelectrics are determined by the presence of these polar nanoclusters [24]. PMN remains cubic to the lowest temperatures measured. One expects that the disorder -type dynamics found in the cubic phase of BaTiOs, characterized by two timescales, is somehow translated into the... [Pg.61]

From induced elementary dipoles to macroscopic properties... [Pg.56]

NMR is rather limited in its frequency range. It has however the important advantage that it is site-specific and allows the detailed determination of the local behaviour of a given elementary dipole. Blinc et al.4 has carried out NMR experiment to verify the deuteron intra-bond motion in deuteron glasses is a pure Arrhenius-like thermally activated process or whether deuteron tunnelling effects become important at low temperatures. [Pg.149]

There are many questions about relaxors. Are they similar to dipolar glasses where elementary dipoles exist on the atomic scale or is the relaxor state indeed characterized by the presence of nanosized polar cluster of variable sizes and orientations. [Pg.158]

The composite system of two different linear molecules has hence four independent elementary dipole dispersion constants, which in London form can be written as ... [Pg.156]

In the case of crystals showing spontaneous polarisation, the elementary dipoles are already... [Pg.346]

In addition to the presence of elementary dipoles, it is important for the polymer to crystallise or partly crystallise into noncentrosymmetric structures. The polymer chains can usually pack together in several different ways. For example, poly(vinyli-dene fluoride), PVF2, can crystallise in four forms. The arrangement of the chains in one nonpolar and one polar form is drawn schematically in Figure 11.11. Namrally, the degree of crystallinity of the... [Pg.347]

As in the case of piezoelectrics, the elementary dipoles will cancel out if the crystallographic unit cell has a centre of symmetry. However, another condition is also needed to produce a spontaneous polarisation, the presence of a unique polar axis, which is a direction in the crystal unrelated by symmetry to any other direction, not even the antiparallel direction. The dipoles lie parallel to the polar axis of the crystal (see Section 5.1.3). Of the 20 piezoelectric crystal classes, only 10 fulfil this criterion and give rise to the pyroelectric effect. The relationship between the appearance of piezoelectricity and pyroelectricity and the symmetry of the crystal is set out in Figure 11.12. [Pg.349]

Naturally, when several units are used, they need to be connected together and this is ensured by supplementary square units, on the same template as for the dipoles constituting a multipole. This case of more complex structures will be tackled in subsequent chapters. In this chapter, only elementary dipole assemblies will be treated, so elementary Formal Graphs (square unit) will be sufficient. [Pg.344]

To illustrate how elementary dipole assemblies are modeled by a Formal Graph, two cases are worth presenting before discussing several case studies. The first case deals with the subject of the isolation or the connection of a dipole assembly with an external source of power the second case deals with the representation of the most important system treated in this chapter, which is the oscillator. [Pg.345]

Association of several dipoles belonging to the same energy variety. Any number of dipoles may be assembled in different mountings, but an elementary dipole assembly is made up only with dipoles sharing the same energy-per-entity (common flow or common effort but not both). [Pg.746]

Here one should note that (0ao/97)vand (9IP/9T)vfor all materials are negative the (at least) partial alignment of the elementary dipoles of the system by the electric field is increasingly counteracted by a rise in temperature that tends to destroy the degree of order. Note further that in vacuo both o and P vanish as is reasonable, empty space permeated by a steady electric field does not carry any entropy. [Pg.299]


See other pages where Elementary dipole is mentioned: [Pg.174]    [Pg.159]    [Pg.400]    [Pg.490]    [Pg.155]    [Pg.158]    [Pg.165]    [Pg.402]    [Pg.24]    [Pg.192]    [Pg.329]    [Pg.251]    [Pg.107]    [Pg.391]    [Pg.346]    [Pg.347]    [Pg.349]    [Pg.351]    [Pg.352]    [Pg.365]    [Pg.365]    [Pg.384]    [Pg.385]    [Pg.154]    [Pg.801]    [Pg.107]    [Pg.344]    [Pg.344]    [Pg.348]    [Pg.740]    [Pg.77]    [Pg.80]    [Pg.609]   
See also in sourсe #XX -- [ Pg.107 ]




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Magnetic dipole moments of elementary particles

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