Magnetic-optical technology

Many industrially and technologically important materials are solids. In addition to the magnetic, optical or mechanical properties and anything else which makes them interesting, a chemist would also want to know... 

The chemical-physical properties of nanocomposite and membrane finds unique place in sensor application due to combinational properties. The basic use of nanocomposite is to the products, which show many folds of improvement on the physical and mechanical properties or on the processing properties upon addition of very minute quantity of nanomaterials [99], Nanoscale particles not only enhance the mechanical properties but also have wide potential in the field of electronic, magnetic, optical, and chemical field. The polymer nanocomposites provide improvement over other known composites in thermal, mechanical, electrical, and even air barrier properties [64-70], Formulation of nanocomposite membranes with suitable polymer, suitable nanoparticles, and the processing technology of the nanocomposite are critical to success factor to dominate the gas sensor product in the market. 

Advances in technology demand the availability of materials with new and sophisticated properties, be it better electrical, magnetic, optical, or mechanical properties or just greater... 

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. 

Semiconductor nanoparticles and QDs are widely used in various fields such as luminescent biolabels [150-152] and have been demonstrated as components in regenerative solar cells [153-155], optical gain devices [24] and electroluminescent devices [23, 156, 157]. DMS have applications in spin-based electronics technologies, or spintronics [158-161]. Spintronic devices such as magnetic-optic switches, magnetic sensors, spin valve transistors and spin LEDs can be activated by implanting ferromagnetic Mn, Ni, Co and Cr in semiconductors [162-165]. Some of the applications of semiconductor nanoparticles or QDs have been explained in this section. 

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