Periodic magnetic structure

As a result of the compression plasma flow action on the sample, highly oriented periodic structures are formed on the silicon surface (Fig. 1, a-c). The structure fragments measure 100-800 nm in diameter and 50-100 pm in length. Application of steady external magnetic field (5=0.1 T) causes the surface structures diameter to decrease and their surface density to enhance. 

The MFM images of the magnetic domain structure of Co film for different Co thicknesses are shown in Fig. 1. Image analysis based on the implementation of autocorrelation function gives the following magnetic domain periods 1.60 nm Co - 5.4 pm, 1.67 nm Co - 3.3 pm, 1.74 nm Co - 2.0 pm, 1.80 nm Co - 0.7 pm, which are in qualitative agreement with the predictions [2]. Besides, it should be noted that domain structure has no preferential direction. 

Modern storage ring facilities use insertion devices, such as wigglers and undulators, in order to increase the intensity of the emitted radiation. Insertion devices consist of periodic structures of permanent magnets. These can... 

A wide variety of molecular properties can be accurately obtained with ADF. The time-dependent DFT implementation " yields UV/Vis spectra (singlet and triplet excitation energies, as well as oscillator strengths), frequency-dependent (hyper)polarizabilities (nonlinear optics), Raman intensities, and van der Waals dispersion coefficients. Rotatory strengths and optical rotatory dispersion (optical properties of chiral molecules ), as well as frequency-dependent dielectric functions for periodic structures, have been implemented as well. NMR chemical shifts and spin-spin couplingsESR (EPR) f-tensors, magnetic and electric hyperfme tensors are available, as well as more standard properties like IR frequencies and intensities, and multipole moments. Relativistic effects (ZORA and spin-orbit coupling) can be included for most properties. 

The concept of defects came about from crystallography. Defects are dismptions of ideal crystal lattice such as vacancies (point defects) or dislocations (linear defects). In numerous liquid crystalline phases, there is variety of defects and many of them are not observed in the solid crystals. A study of defects in liquid crystals is very important from both the academic and practical points of view [7,8]. Defects in liquid crystals are very useful for (i) identification of different phases by microscopic observation of the characteristic defects (ii) study of the elastic properties by observation of defect interactions (iii) understanding of the three-dimensional periodic structures (e.g., the blue phase in cholesterics) using a new concept of lattices of defects (iv) modelling of fundamental physical phenomena such as magnetic monopoles, interaction of quarks, etc. In the optical technology, defects usually play the detrimental role examples are defect walls in the twist nematic cells, shock instability in ferroelectric smectics, Grandjean disclinations in cholesteric cells used in dye microlasers, etc. However, more recently, defect structures find their applications in three-dimensional photonic crystals (e.g. blue phases), the bistable displays and smart memory cards. 

From eq. (7.12), it is obvious that the system will choose as the magnetic periodicity q the value of q for which (q) is a maximum. The detailed discussion of the relationship of q) to the electronic structure and in particular... 

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