Relation Between High-Frequency Properties and Direction of Anisotropy Magnetic Field in Magnetic Thin Film for RF Inductor Applications

A relation between high-frequency properties, and angle theta of the easy axis in soft magnetic film and ac applied field was investigated in order to fabricate the film for RF spiral inductor without a localized EMI (Electro-Magnetic Interference). This relationship was measured using a soft CoFeSiO/SiO2 granular multilayer magnetic thin film and simulated by using LLG (Landau-Lifshitz-Gilbert) micromagnetic simulator. The measured and calculated frequency dependence of the film's complex relative permeability, mu(r)' and mu(r)'' compared well with 10% mean error. The real part of complex relative permeability mu(r)' was dependent on approximately sin(2) theta. The ferromagnetic resonance (FMR) frequency, f(r), and the FMR half-width, Delta f(r) were not dependent on the angle theta. They were estimated to be 2.54 GHz and 0.3 GHz, respectively. These results are significant for the design of various magnetic thin film spiral inductors in RF integrated circuits without localized EMI.ArticleIEEE TRANSACTIONS ON MAGNETICS. 48(11):4515-4517 (2012)journal articl

Study on the Transformation of Zinc by Electric Resistance in Connection with Eutectic Phenomena

Accurate measurements of the electric resistance of zinc were made by the potentiometer method in the range of temperature from room temperature up to 350℃. The anomalous changes were observed at the temperatures, 170, 200, 230 and 320℃. The first two temperatures were explained respectively to be the eutectic temperatures of the solders, Pt-Sn-Zn and Sn-Zn systems, used to solder the potential lead and the specimen ; 230℃ to be the temperature of second separation in the former solder ; 320℃ to be the eutectic temperature of the alloy, Pd-Zn system formed in the specimen. From a conception explaining the eutectic phenomenon, 170°, 200°and 320℃ were considered to be anomalies of zinc itself

Heterocyclic Compounds Containing Phosphorus. I : On the Syntheses of Five Membered Monothio Phosphates

Cyclic monothio phosphates were prepared by the reaction of glycols and thio phosphoryl chloride. Their characteristics are shown in Table 2, 3 and 4. In order to confirm the structure, a series of cyclic phosphites of known construction were allowed to react with sulfur to give cyclic monothio phosphates, and physical and analytical data show that the products prepared by the both methods were the same ones

FeNiSiO/SiO2 multi-layer granular magnetic films with high-resistivity

ArticleTransactions of the Materials Research Society of Japan. 34(1):9-13 (2009)journal articl

CoFeSiO/SiO(2) Multilayer Granular Films With Very Narrow Ferromagnetic Resonant Linewidth

In order to fabricate GHz-band micro-magnetic devices, we have investigated the high-frequency permeability of CoFeSiO/SiO multilayer granular films comprising alternate stacks of granular and insulator layers, which can enable us to control the magnetic grain size and intergrain spacing along the film thickness direction independent of each other. A very narrow ferromagnetic resonance (FMR) linewidth was obtained under specific film conditions. A sharp FMR peak was obtained for granular layer and insulator layer thicknesses of 6 and 1 nm, respectively. The CoFe/SiO(2) volume ratio of the granular layer has a strong influence on the FMR linewidth. A high CoFe/SiO(2) volume ratio resulted in a very narrow FMR linewidth. HR-TEM observation of a film with a high CoFe/SiO(2) volume ratio revealed a well-defined multilayer granular structure and a homogeneous CoFe grain size, which seem to be necessary for obtaining a very narrow FMR linewidth. The narrowest FMR linewidth observed in this study is 420 MHz, for an FMR frequency of 2.4 GHz, a permeability of 380, and a damping factor alpha of 0.007.ArticleIEEE TRANSACTIONS ON MAGNETICS. 45(10):4290-4293 (2009)journal articl