INVESTIGATION INTO PERPENDICULAR ANISOTROPY COBALT-CHROMIUM FILMS WITH APPLICATION TO WINCHESTER COMPUTER DISCS by NADER MAHVAN BSc, MSc , RF-spUttered CoCr films have been characterized for a variety o f deposition conditions, and the most effective parameters which bring about perpendicular anisotropy have been evaluated. In particular bias sputtering has been noted for its role in improving ...

We introduce a method to obtain the specific heat of quantum impurity models via a direct calculation of the impurity internal energy requiring only the evaluation of local quantitieswithin a single numerical renormalization group (NRG) calculation for the total system. For the Anderson impurity model we show that the impurity internal energy can be expressed as a sum of purely local static cor...

We have performed density-functional pseudopotential calculations to investigate the electronic structure, atomic configurations, and formation energies of native point defects and impurities in AlN. For the native defects, the nitrogen vacancy has the lowest formation energy in p-type material and the aluminum vacancy has the lowest formation energy in n-type material. Under n-type conditions ...

During the synthesis of the bulk drug Raloxifene hydrochloride, eight impurities were observed, four of which were found to be new. All of the impurities were detected using the gradient high performance liquid chromatographic (HPLC) method, whose area percentages ranged from 0.05 to 0.1%. LCMS was performed to identify the mass number of these impurities, and a systematic study was carried out...

Water adsorption and dissociation on the perfect, oxygen containing and nitrogen vacancy containing Ta3N5(100) surfaces are systematically studied by density functional theory calculations. The results show that the perfect Ta3N5(100) surface is very active for water dissociation because of the dangling bonds formed on the perfect Ta3N5(100) surface. The presence of oxygen on the surface is abl...

1. A method is described for the preparation of pepsinogen from swine gastric mucosae which consists of extraction and fractional precipitation with ammonium sulfate solutions followed by two precipitations with a copper hydroxide reagent under particular conditions. Crystallization as very thin needles takes place at 10 degrees C., pH 5.0 and from 0.4 saturated ammonium sulfate solution contai...

Fe is an impurity in most leach liquors. Its coexistence with copper in leaching solution of chalcopyrite (CuFeS2) which is the most important mineral of copper creates major extraction problems. Hydrochloric acid dissolves both copper and iron during chloride leaching of this mineral. Separation of Fe from Cu is thus necessary to obtain pure copper. This paper presents a novel metho...

Silicon nitride films were deposited using an atmospheric pressure plasma source. The discharge was produced by flowing nitrogen and helium through two perforated metal electrodes that were driven by 13.56 MHz radio frequency power. Deposition occurred by mixing the plasma effluent with silane and directing the flow onto a rotating silicon wafer heated to between 100 ̊C and 500 ̊C. Film growth ra...

We investigate the behavior of impurity fields immersed in a larger condensate field in various dimensions. We discuss the localization of a single impurity field within a condensate and note the effects of surface energy. We derive the functional form of the attractive condensate-mediated interaction between two impurities. Generalizing the analysis to N impurity fields, we show that within va...

We study an Anderson impurity in a semiconducting host using the density matrix renormalization group technique. We use the U = 0 one–dimensional Anderson Hamiltonian at half filling as the semiconducting host since it has a hybridization gap. By varying the hybridization of the host, we can control the size of the semiconducting gap. We consider chains with 25 sites and we place the Anderson i...