Preparation Of One-dimensional Magnetic Nanostructures And State-Control Of A Particle In One-dimensional Superlattice

α-Fe₂O₃ is an n type semiconductor with a middling gap(2.leV),it's a magnetic semiconductor with its environment-friendly.Ferric oxide has attracted extraordinary attention for their special physical properties and potential applications in magnetic access memory,light/gas sensors and biomedicine,α-Fe₂O₃ is a perfectly carrier to achieve the associativity of nanoelectronics and spinelectronics.It makes people pay more attention to the question that how to achieve the exact control in the process ofα-Fe₂O₃'s growth to get the one-dimensional nanostructure with special scale and good monodispersity because the physical properties depend on the microstrcture of the nanomaterial.This letter discussed the preparation of one-dimensional magnetic nanostmctures and state-control of a particle in one-dimensional superlattice wants to built a model of nano spin device.α-Fe₂O₃ one-dimensional nanostructure(nanobelts and nanowires with controllable diameters)arrays have been successfully synthesized by thermally oxidizing iron foil directly.The morphologies and microstructures of these synthesized arrays depend much on the growth conditions such as the oxygen pressure,temperature and reaction time. We found that the growth ofα-Fe₂O₃ one-dimensional nanostructures follows a top-growth mechanism,in which the ratio of iron and oxygen atoms near the growth spots plays a key role.We do the thermally oxidizing for one or several times to synthesized the nanoneedles and other nanostructure successfully.In addition,we deoxidized theα-Fe₂O₃ one-dimensional nanostructures successfully to make Fe₃O₄ nanowires, and we discussed about it.The chapter four treats a single particle system in an optical superlattice of double-cosine form from two pairs of counter- propagating laser beams.By applying the Riccati transformation we obtain two sets of exact Bloch solutions of simple forms,which are associated with the different boundary conditions and eigenenergies.Some interesting physical properties described by the exact solutions are discussed in detail. Some properties of the solutions,such as the stabilities,periodicities and the piecewise continuities of the spatial derivatives,are discussed analytically and the corresponding profiles of wave functions are illustrated numerically.The eigenenergies are obtained in terms of the wave-vector and strengths of the potentials,and may be positive or negative,which corresponds to positive-energy or negative-energy state. By using some laser beams to adjust the boundary conditions,one can control the system to required state.As an application of the exact solutions a simple instance of planar rotor is treated approximately and some advantages of the new perturbation method are displayed.After all, by extending the results to many-particle system and coupling the external motional states with the internal electronic states of the particles, we can perform the quantum logic operations based on the double-cosine potential with a large well depth.