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.
Passive coplanar isolator with barium ferrite thin films
The development of integrated devices combining a ferrite is a major focus of current research. Barium hexaferrite (BaFe/sub 12/O/sub 19/ or BaM), which exhibits a high anisotropy field and high coercive force are deposited on alumina substrate using an RF sputtering system. After deposition BaM films are amorphous and a post deposition thermal annealing is needed to obtain magnetic properties. The saturation magnetization and coercive force was about 500 mT and 330 kA/m. After that, coplanar lines were made with BaM thin films on alumina substrates and with gold conductor. The transmission coefficients of a barium ferrite coplanar isolator are measured up to 55 GHz. The measurements of transmission parameters S/sub 12/ and S/sub 21/ was performed by a 65 GHz vector network analyzer and a probing system. First experimental results showed an isolation of 3.3 dB/cm at 50 GHz.
Thermodynamics on the Carbochlorination of Titanium-bearing Ores
The equilibrium compositions of the multi-component, multi-phase and multi-reaction system of carbochlorination of titanium-bearing ores are calculated with HSC, a computational chemistry software. The thermodynamic equilibrium calculation of the reaction system shows that a complete conversion of titanium-bearing ores is feasible at a temperature near 200oC. At temperatures ranging from 800 to 1600oC, the products of the reaction system are all in gaseous phase. Thermodynamic analysis accords with the industrial practice. The simulated results provide reasonable scientific basis for improving suitable technological conditions of the carbochlorination reduction.