Notesale: Turn your study into money

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General applications - nanotechnology
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Apart from various electronic effects in materials in the quantum or

nano level, the spin dynamics assumes a great importance
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g
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It should be pointed out here that in the field of ‘ferroelectricity’, there is also a new
class of materials like lithium niobate and lithium tantalate, which show high non-volatile
memory called FRAM, and there is a possibility of 'infinite memory' in such materials
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This is based on the very basic fact that electrons have spin
as well as charge
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The advantages of
‘spintronics devices’ over traditional ‘semiconductor devices’ include the following :
(a) Much faster switching times,
(b) Reduced power consumption,
(c) Non-volatile memory, and
(d) Increasing levels of miniaturisation
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There are several advantages associated with the use of spinpolarised current rather than external magnetic fields, i
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the most important being no more
(or much reduced) cross-talk and low power consumption
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The
‘spintronics’ is quite a new area
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Gaint magnetoresistance (GMR)
The 2007 Nobel prize for Physics was awarded to Albert Fert and Peter Grunberg “for their
discovery of Giant Magnetoresistance (GMR)”
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The effect manifests itself as a significant decrease in electrical resistance in the
presence of a magnetic field
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If GMR is to work, structures consisting of
layers that are only a few atoms thick have to be produced
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The discovery was made in 1988, and it was realised that this effect would make it possible to
manufacture very sensitive magnetic read heads for hard disks
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This invention is responsible for the ultra-high density disk drives in MP3
players,digital video recorders, and computer notebooks

Nonophotonics
Photonic crystals are new types of optical materials, in which small dielectric cells with the
size of optical wavelength (from several 100 nm to several 10 m) are periodically arranged
in two- or three-dimensions
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Semiconductor crystals such as Si have a special energy range called a bandgap,
within which the electrons cannot have corresponding energy
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In a photonic crystal, the light with a frequency in the PBG cannot exist
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For realizing high-performance lasers or ultra-small integrated optical circuits, PBG is
indispensable
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Current medical treatments are usually indiscriminate and affect healthy body cells
as well as the damaged or pathogenic cells, either because surgery is required or because the
drugs given have no way of distinguishing between body cells and harmful cells
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Other
treatments such as chemotherapy for cancer and antibiotics for infections can cause side
effects and cause damage to healthy cells
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Nanoparticles make good
diagnostic tools because they can reach lots of places within the body easily through the
blood stream and are also very sensitive due to the size
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It is into this category that plasmon active gold nanoparticles
(PAGNs) fall
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This is advantageous over existing treatments
because it allows the relevant drugs to be administered directly to the desired area e
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to the

cancer cells in a tumour or to the bacterial cells in an infection rather than generally
administered into the bloodstream in the local area
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This
enables these nanoparticles to eradicate targeted tumors
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Therapeutic Agent Delivery - Therapeutic agents can also be coated onto the surface of gold
nanoparticles
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Nanoprobes Quantum dot imaging of cells, DNA, Protein detection See also the slides
Nanostructured materials in energy conversion devices – see the slides



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