In this paper, we experimentally investigated DC and transition noise characteristics of media with various OR values. OR was controlled by adjusting the textured NiP surface morphology resulting in different "line density" prior to depositing the same magnetic layered films. The observed results suggested that with increasing OR, DC noise is significantly reduced, while the media transition noise gradually increases. As a result of significant DC noise contribution to the total media noise, the normalized total media noise power of higher OR media is lower over a wide range of recording densities. For high density low M/sup r/t designs, reducing DC noise by increasing OR, inspite of a gain in transition noise, becomes an effective means to increasing areal density.

Summary form only given. It has been reported that media with high in-plane orientation ratio (OR) may enhance thermal stability and strong in-plane orientation of the Co c-axis in isotropic glass media is needed to improve recording performance. In this work, a systematic study of thermal stability and recording characteristics was performed on glass media with varying in-plane crystallographic orientation [random 2D-to-3D] and preferred orientation [(10.0) vs (11.0)]. In addition, the effect of in-plane OR on thermal stability was investigated for the media deposited onto both mechanically textured and non-textured polish only AlNiP substrates.

A recording density of 130 Gb/in/sup 2/ was achieved using thermally stable conventional CoCrPtB longitudinal media. The high in-plane orientation ratio (OR) of the media resulted in an excellent recording performance due to a narrow switching field distribution as well as a high thermal stability caused by narrow energy barrier distribution. The low noise is attributed to the fully isolated fine grains with a narrow size distribution. A good in-plane c axis crystallographic texture was achieved by using an optimum multilayered structure of underlayer and magnetic layers. A detailed study of high OR media is reported by characterizing the magnetic, microstructural, and read/write properties.

A 2D model to study the effect of crystal orientation on interfacial structural misfit and Co grain defect density for hcp Co/bcc Cr thin him system has been introduced. The magnitude of misfit depends strongly on the Co/Cr orientation, their respective lattice parameters, the grain size and to a Lesser extend, the relative lattice orientation across the interface. However, the modeling results showed that by introducing lattice defects such as fee stacking faults and misfit dislocations in the Co layer, one can greatly reduce this misfit and relax the interface.

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The microstructure of CoPtCr alloy thin films, sputter deposited on Cr-underlayers varying in thickness from 25 to 1300 Å, is examined. The cross-sectional as well as plane-view high resolution transmission electron microscopy (HRTEM) of these films revealed that fine Cr-underlayer grains nucleate randomly and grow on the surface of a textured NiP substrate during the early stage of sputter deposition. The heterogeneously nucleated Cr grains result in the formation of columnar grains through competitive growth. The width of columnar grains gradually increased with film thickness and saturated at a thickness of about 850 Å Cr-underlayer films. High resolution electron microscopy of these films showed the onset of physical separation between columnar grains occurred between 250 and 600 Å. The study provides insights into the evolution of thin film microstructure during sputter deposition and into the reported low noise in CoPtCr/Cr films with ultra-thin Cr underlayers

AbstractDie Thermo‐EMK von Alkalimetall‐Alkalimetallhalogenid‐Mischschmelzen wird auf der Basis der Modelle von Pitzer (vollständige Dissoziation des Metalls in Kation und Elektron) und Rice (keine Dissoziation des Metalls) berechnet.

The reduction of N2O has been studied by cyclic voltammetry for a variety of solution conditions. At a platinum electrode with a freshly formed oxide film N2O is reduced by an adsorption process. The reduction process is blocked by the presence of NO, NO2−, PbO2− or I− in the sample solution. At more negative potentials the N2O appears to be repelled from the surface by double layer effects.

Synopsis A simple, flexible test facility has been devised which is suitable for examining the effects of trace gases on the degradation of materials under conditions approximating to those of free atmospheric exposure.

By following the variation of absorptivity and energy of the principal electronic transitions with addition of ligand it is shown that CoCl2 gives rise to CoCl42− in γ-butyrolactone and Co(NO3)2 gives rise to dodecahedral Co(NO3)42− in γ-butyrolactone, propylene carbonate, and acetone.

The products from the oxidation of several phenols in the presence of 4-aminoantipyrine have been isolated and their p.m.r. spectra examined. The results confirm the proposed formation of p-quinoneimide adducts and the elimination of the para-group in the case of reactive p-substituted phenols. Data from ortho substituted phenols reveal the formation of syn and anti geometrical isomers of the quinoneimide. In contrast, when the starting phenol has a meta-substituent, only a single isomer, the less hindered anti form, is obtained. An unusually large anisotropic effect of the antipyryl group, causing a deshielding of the closest proton on the quinoneimide ring, has been found. In the reaction between p-benzoquinone and 4-aminoantipyrine, the color obtained is due to the formation of the p-quinoneimide, and not to a charge-transfer complex.

[Ni(Aox)4Cl2] (Aox = acetaldoxime), [Ni(Acm)4(H2O)2]Cl2 (Acm = acetamide), Ni(Cy)3Cl2 (Cy = cyclohexanone oxime), and [Ni(cap)6]Cl2(Cap = caprolactam) have been prepared. Their solution electronic spectra indicate approximately octahedral environments for Ni(II) while solid Ni(Aox)4Cl2 shows a small tetragonal distortion. The i.r. spectra can be accounted for by oxime bonding to Ni via nitrogen and amide bonding to Ni via oxygen alone.

Since the Tanabe-Sugano diagrams are linear over wide ranges of Δ, the ligand field strength, it is possible to write the energy of any electronic transition in the form: E = a(ΔBC) + b(BC) + c(BΔ) + d(CΔ) + Eb + fC + gΔ + h where B and C are the Racah parameters. The coefficients a through h were calculated from the original matrices for the lower transitions of d2 through d8 ions and a procedure developed to obtain the Δ, B and C values which give the best fit to an experimental spectrum.

AbstractEs wird über Messungen der Thermokraft mit reversiblen Ag‐Elektroden an polykristallinen Proben von Ag4MJ5 (M: K, Rb) und an geschmolzenen Gemischen der gleichen Zusammensetzung (M: K, Rb, Cs) berichtet.

The diffusion coefficients of Cu(I), Ag(I) and Au(I) ions in molten KCl were found to be 2·14 ± 0·35, 2·03 ± 0·08 and 2·2 × 10−5 cm2/s respectively by chronopotentiometry with a Pt indicator and Pt reference electrode.

The Seebeck coefficient, εT, of the thermocell Ag(T)/AgNO3 in NaNO3 − KNO3/Ag (T + ΔT) was measured as a function of silver nitrate concentration and temperature. Extrapolation of the results to unit mole fraction, N, of AgNO3 gave the value εT0 = − 277.5 − 0.136T °C (µV deg−1).For several mixed melts of AgNO3 and an alkali nitrate the function [Formula: see text] was calculated and shown to be linear in N. P was extrapolated to finite values for the pure alkali nitrates.

From the e.m.f. values of isothermal cells of the type Ag|AgX||AgY in BY|Ag and of thermogalvanic potentials an e.m.f. series has been constructed which relates the electrode potentials in several individual molten alkali metal salts containing NO−2, NO−3, Cl−, SO2−4 or CO2−3 to the aqueous hydrogen electrode at 25°C. In increasing order of stability to oxidation we have the series CO2−3 < NO−3 < Cl− < SO2−4, and in increasing order of stability of solutions of silver(I) the series SO2−4 < NO−3 < CO2−3 < NO−2 < Cl−. Data pertaining to the free energies of formation of HNO3 at 400°C and H2CO3 and H2SO4 at 550°C are derived.