Effects of stoichiometry on the magnetic and structural properties of perpendicular barium ferrite thin film media
The effects of stoichiometry factor n on the magnetic and structural properties of perpendicular barium ferrite thin films with composition of BaO.n(Fe/sub 2/O/sub 3/) were systematically investigated. Within the range 2.2<n<6, the c-axis for barium ferrite thin films can be oriented perpendicularly by the use of a Pt underlayer and with optimized processing conditions. Perpendicular c-axis orientation becomes worse as n decreases from 6 to 2.2. The average grain size was greatly reduced from about 2000 /spl Aring/ to 300 /spl Aring/ with the decrease of n. The decrease of the grain size can be related to the existence of nonmagnetic phase BaFe/sub 2/O/sub 4/, which was observed by X-ray diffraction.
Crystallographic properties of magnetron sputtered barium ferrite films
Abstract The development of devices combining a ferrite with a semiconductor chip is a major focus of current research. Barium hexaferrite (BaFe12O19 or BaM) thick films are deposited here using a RF magnetron sputtering system. Films are amorphous and non magnetic after deposition. Post-deposition thermal annealing is employed to make the films crystallize. The effects of the substrate, thermal annealing process, thickness, substrate temperature on crystallographic properties and stoichiometry are studied using a X-ray diffractometry (XRD) and Rutherford back-scattering (RBS). The in-depth homogeneity of Ba, Fe and O is evaluated by secondary ion mass spectroscopy (SIMS). The study shows a good crystallization of BaM films and there is a preferential orientation among the crystallographic planes (1 0 1), (2 0 0), (2 0 3), (1 0 2), (1 1 0) and (2 0 5) when BaM films are prepared at low RF power and when the substrate is heated. For several elaboration parameters, grains size is in the range of 25 and 40 nm and BaM films are stoichiometric with regard to the target stoichiometry.
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.