Magnetically oriented films

Fig. 1. X- ay difFiaction photc iaphs of electiically (left) and magnetically ( riigjit) oriented films of PBLG. The field stiengths used were, 250 V/cm and 9.6 kG respectively for the electrically and the magnetically oriented films by courtesy of Mr. S. Ejiri...

In magnetically oriented films of PBLG the surface cha is not detected (51). This sbows that the molecular clusters are distributed faidy equally in both directions and that the magnetic-field orientatimi is caused by induced (m etic) dipoles of the molecular cluster. 

The angular distribution of polarized components of fluorescence intensity of electrically or magnetically oriented films of pcdypeptides show the pattern similar to those typical of the uniaxia% miented film. The degree of orientation of the films as expected from the contour of the pattern, is not so good despite the excellent (mentation of the films, which m indicate that most of the fluorescent molecules are introduced into the gap regicnis that may possibly form amorphous regions. 

It may be ctmsidered that the molecular cluster in which rod-lihe molecules align neatly parallel to the cluster axis, itself forms a crystallite. The intensity of the X-ray diffraction for the incident beam that is perpendicular to the magnetically oriented film of polypeptide, /, is well expresred in the form (38) ... 

Rgura 20 Temperature dqKodeocc of piezoelectric constant for magnetically oriented film of poly- Y-beazyl-L- ulamBie. (From Ref. S3.)... 

Thin-film XRD is important in many technological applications, because of its abilities to accurately determine strains and to uniquely identify the presence and composition of phases. In semiconduaor and optical materials applications, XRD is used to measure the strain state, orientation, and defects in epitaxial thin films, which affect the film s electronic and optical properties. For magnetic thin films, it is used to identify phases and to determine preferred orientations, since these can determine magnetic properties. In metallurgical applications, it is used to determine strains in surfiice layers and thin films, which influence their mechanical properties. For packaging materials, XRD can be used to investigate diffusion and phase formation at interfaces... 

In this review the definition of orientation and orientation functions or orientation averages will be considered in detail. This will be followed by a comprehensive account of the information which can be obtained by three spectroscopic techniques, infra-red and Raman spectroscopy and broad line nuclear magnetic resonance. The use of polarized fluorescence will not be discussed here, but is the subject of a contemporary review article by the author and J. H. Nobbs 1. The present review will be completed by consideration of the information which has been obtained on the development of molecular orientation in polyethylene terephthalate and poly(tetramethylene terephthalate) where there are also clearly defined changes in the conformation of the molecule. In this paper, particular attention will be given to the characterization of biaxially oriented films. Previous reviews of this subject have been given by the author and his colleagues, but have been concerned with discussion of results for uniaxially oriented systems only2,3). 

On the basis of the observations, the enhancements of the p-values for the Q-Zni x MrLxS monolayer films can most likely be ascribed to the interaction between Mn ion as a magnetic ion and the external magnetic field. The enhancements are probably caused by magnetic orientation of the Q-Zni-xiMn S on the quartz substrates. 

Fig. 2.18. (a) The even (upper panel) and odd (lower panel) SH responses of a 20 nm Gd(0001) film at 90 K using 815nm/35fs laser pulses. Transient reflectivity change is also displayed in the upper panel (solid black curve). The inset shows the experimental scheme with the magnetization oriented perpendicular to the plane of incidence, (b) The oscillatory part of the even and odd SH fields extracted from (a). The inset shows the corresponding FT spectra. From [59]... 

Z Ali-Adib, K Davidson, H Nooshin, and RH Tredgold, Magnetic orientation of phthalocyani-nato-polysiloxanes, Thin Solid Films, 201 187-195, 1991. 

Figures 15, 16, and 17 depict Cu + spectra of air-dry smectites in oriented films at 0° and 90° to the applied magnetic field.

Table 4. Maximum induced dipole moments of the molecular cluster in magnetically oriented polypeptide films and its estimated birefringences at complete orientation...

Relationship between elasticity and orientational order As remarked in chapter I, a uniformly oriented film of nematic liquid crystal may be prepared by prior treatment of the surfaces with which it is in contact. If the preferred orientation imposed by the surfaces is perturbed, let us say by a magnetic field, a curvature strain will be introduced in the medium. The theory of such a deformation will be discussed at length in 3.2 for the present it will suffice to state some of the important results. The free energy per unit volume of the deformed medium relative to the state of uniform orientation is... 

Biaxially oriented films of PET polyesters are frequently used in the field of magnetic recording media, such as audio tapes, video tapes, computer tapes, and floppy disks. With the tendency to reduce the size and weight of electric and electronic equipment and to improve their performance, the demands become increasingly exacting. 

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