Field-oriented texture type

Figure 6.1 Different types of compact 3D metal deposits according to Fischer [6.8]. (a) Field-oriented isolation type (FI) of an Ag deposit (b) field-oriented texture type (FT). Cross section of Cu deposit from acid CUSO4 solution with addition of /5-naphthaquinoline (c) base-oriented reproduction type (BR). Cross section of Cu deposit (d) randomly-oriented dispersion type (RD). Cross section of Cu deposit from acid CuSO solution with addition of naphthaquinoline.

Figure 7.15 Winand diagram. Depending on current density and inhibition activity, Fischer classified four structural types of preferential observation a base-oriented reproduction type BR, a field-oriented texture type FT, an un-oriented dispersion type UD, and the field-oriented isolation type FI, which is near the origin of deposition or formation of isolated crystals and is not often observed.

The phenomenological classification of compact 3D Me deposits by Fischer (cf. Section 6.1) can be related to the nucleation and growth parameters discussed above. For example, the field-oriented isolation (FI) and texture (FT) types are caused by electric field-enhanced normal growth, the base-oriented reproduction (B t3 e corresponds to a relatively low nucleation rate and comparable normal and lateral growth rates, and the randomly-oriented dispersion (RD) type to an enhanced nucleation rate. 

In most deposits, one-dimensional texture can be observed using electron diffraction. X-ray diffraction, or electron micrography. Two types prevail " the lateral growth ( substrate-oriented deposit " ), in which the most densely populated crystal plane is parallel to the substrate surface, and the outward growth ( field-oriented deposit " ) in which most densely packed arrays of atoms extend perpendicularly to the surface. However, other orientations are also found. " Thus, cobalt, hexagonal nickel, and hexagonal silver tend to have the (1010) plane parallel to the surface. 

The structure of metallic deposits is determined primarily by the size, shape (faceting), type of arrangement, and mutual orientation of the crystallites. Two factors may influence the orientation and spatial alignment of the microcrystals in electrocrystallization the field direction (or direction of the electric current) and the nature of the substrate. The deposits are said to have texture when the crystallites are highly oriented in certain directions. Epitaxy implies that the lattice is altered under the influence of the substrate. 

A theoretical consideration of the case of a pitch that is comparable to the layer thickness for a purely dielectric destabilization of a planar texture in a field 11 has been given both numerically [122] and analytically [123, 124]. In the latter case the perturbation theory was used to search for the structure of the director field just above the threshold of the instability. Two variables, the polar angle 6 and the azimuthal angle 0 were considered, with orientation of the director at opposite walls differing by a twist angle a (pretilt angles at boundaries were also taken into account). It has been shown that two types of instability can be observed depending on the elastic moduli of the material a total twist of the structure between... 

The textural changes in the droplet morphology under the influence of applied electric field of 2.2 V/p for DPDLC films doped with optimum concentration of 0.015 wt% dye are shown in Fig. 7.6. It is observed that the randomly oriented LC droplets in the polymer matrix demonstrate maltese type crosses as a consequence of high order alignment of nematic directors along the direction of electric field. 

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