Pole figures measurements

The electrodeposited precursor films, annealed in air at 870 °C in the presence of a TBSBCCO pellet, produce a biaxial textured Tl-1223 phase, as confirmed by an XRD pole-figure measurement. The omega and phi scans indicate full-width at half-maximum (FWHM) values of only 0.92° and 0.6°, respectively, which indicates a very high-quality film. The superconductive transition temperature of the Tl-1223 film, determined resistively, was about 110 K. Figure 7.11... 

WIMV routine gave similar ODF to those obtained from individual pole figure measurement. 

Abstract. Structural properties of rubrene thin films on cleaved mica (001) surfaces were investigated by optical microscopy and x-ray diffraction. Optical microscopy shows, that the crystallization of rubrene results in formation of spherulites. X-ray specular diffraction reveals polycrystalline and polymorphic nature of rubrene. The pole figure measurements of films prepared at low deposition rates reveal orthorhombic structure and indicate fiber textures with crystallographic planes (121), (131) and (141) preferentially oriented parallel to the substrate surface. High deposition rate thin films in addition show polymorphism, corroborating the existence of the orthorhombic and the triclinic phase. 

X-ray diffraction pole figure measurements on a poly(vinyl fluoride) film [91]. 

Figure 3 shows a Siemens texture goniometer. The technique of pole figure measurement in the reflection mode was proposed by Schulz as early as 1949... 

Fig. 2. Schematic view of the experimental arrangement for a pole figure measure in reflection mode...

For thin specimens it is also possible to perform pole figure measurements in transmission mode [2]. Because of the difficulty of preparing thin specimens with a constant thickness this last mode is not often used today for x ray diffraction. 

With such a definition, a specimen without preferred orientations, i.e. a random specimen will have a pole density Phi ((/ , x) = 1 whatever the ((/ , x) considered direction and whatever the hi reflection considered. One can also note that the integral over the half sphere of the pole figure can be directly determined if the complete pole figure is available. As explained previously, this is not the case for pole figures measured in reflection mode which are necessarily incomplete. 

Once again there are two ways to obtain the required information which is here the normalization factor Ni. The first is again based on measurements of a random specimen under exactly the same experimental conditions as for the pole figure measurements. The pole density is then deduced through the relation,... 

The ODF, f g), sometimes also called the texture function, is the best tool to characterize the crystallographic texture which mainly induces the anisotropic behavior of a polycrystalline aggregate. The texture analysis consists of the calculation of f g) starting from experimental data, i.e. from pole figure measurements. 

There are today standard computer controlled x ray diffraction equipments for pole figure measurements as well as software packages for ODF calculation so that only a general knowledge about texture analysis is usually required of researchers who intend to study the anisotropic behavior of materials. Moreover, many papers have demonstrated how physical or mechanical properties can be calculated in textured materials. This is especially true for cubic metals and alloys and, to a lesser extent, for hexagonal alloys. There remain, therefore, many studies to be undertaken, particularly for non-metallic polycrystalline materials. 

X-ray pole figure measurement is commonly used to study the crystallographic alignment of oriented thin films on substrates. Figures 17-3(a) and (b) 0 1 2)X-raypole... 

The value of the approach using dichroic ratios coupled with a knowledge of the assignments of peaks is further illustrated by measurements on plain polyethylene films [2]. The production process leads to a rather complex orientation pattern. The molten polymer is extruded as a thin, hollow cylinder, in what may be termed the machine direction. It is simultaneously expanded in a plane perpendicular to the machine direction by the application of internal pressure. Additional variables are the extrusion temperature and the rate at which the blown film has been cooled. The resulting orientation behaviour is best studied by x-ray diffraction pole figure measurements [3,4,5] but the infrared approach provides a relatively simple means for obtaining a useful amount of information, particularly for the behaviour of chains in amorphous regions. 

Figure 6 shows (0002) pole figure measured from radial-tangential plane of sample 1. High pole concentration was clearly observed. This pole concentration indicates that the HAp crystalline c-axis are oriented to the similar direction. 

We traced the (110) plane by pole figure measurement to calculate the crystalline orientation for uniaxially stretched films. The orientation gradually increased by increasing stretching ratio to its maximum above 200% stretching. 

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