Magnetic properties of Sm(Co/sub bal/Fe/sub 0.31/Zr/sub 0.05/Cu/sub 0.04/B/sub x/)/sub z/ alloys and their melt-spun materials (x=0.02--0.04,z=7.5--12)
Cast alloys and melt-spun ribbons with nominal compositions of Sm(Co/sub bal/Fe/sub 0.31/Zr/sub 0.05/Cu/sub 0.04/B/sub x/)/sub z/ (x=0.02-0.04,z=7.5-12) have been synthesized and characterized in a temperature range of 10-1273 K and at fields up to 5T. The main phase in the as-cast alloys exhibited a Th/sub 2/Ni/sub 17/ type structure, with a strong uniaxial anisotropy. Minor phases with a TbCu/sub 7/ and/or CaCu/sub 5/ structure emerged as z (3d/R) decreased. As a result, the anisotropy field (H/sub A/) increased from 67 to 120 kOe, while 4/spl pi/M/sub s/ fell from 12.8 to 10.5 kG at 300 K when z was decreased from 12 to 7.5. For melt-spun ribbons, they are nano-structured in nature and magnetically hard, even in the as-spun state. By lowering the value of z(3d/R) and raising the B content, a finer microstructure and a higher H/sub ci/ were obtained. Hard magnetic properties of H/sub ci/=4.9-12 kOe, 4/spl pi/M/sub s/=9.0-12.0 kG at 300 K have been obtained from ribbon samples. Among them, Sm(Co/sub bal/Fe/sub 0.31/Zr/sub 0.05/Cu/sub 0.04/B/sub 0.02/)/sub 10/ ribbon showed the highest (BH)/sub max/ of 10.8 MGOe at 300 K. A Henkel plot analysis suggested the existence of exchange-coupling interaction between the magnetically hard and soft phases in the ribbon materials.
Magnetic Properties of Sm(Co Fe Zr Cu B ) Alloys and Their Melt-Spun Materials - -
Abstract— Cast alloys and melt-spun ribbons with nom-inal compositions of Sm(Co bal Fe 0 31 Zr 0 05 Cu 0 04 B x ) z (x = 0 02 – 0 04 z=75 – 12) have been synthesized andcharacterized in a temperature range of 10–1273 K and at fieldsup to 5T. The main phase in the as-cast alloys exhibited a Th 2 Ni 17 type structure, with a strong uniaxial anisotropy. Minor phaseswith a TbCu 7 and/or CaCu 5 structure emerged as z (3d/R)decreased. As a result, the anisotropy field ( ) increased from67 to 120 kOe, while 4 fell from 12.8 to 10.5 kG at 300 Kwhen z was decreased from 12 to 7.5. For melt-spun ribbons,they are nano-structured in nature and magnetically hard, evenin the as-spun state. By lowering the value of z (3d/R) and raisingthe B content, a finer microstructure and a higher wereobtained. Hard magnetic properties of =49 – 12 kOe, 4 =9 0 – 12 0 kG at 300 K have been obtained from ribbonsamples. Among them, Sm(Co bal Fe 0 31 Zr 0 05 Cu 0 04 B 0 02 ) 10 ribbon showed the highest ( ) max of 10.8 MGOe at 300 K. AHenkel plot analysis suggested the existence of exchange-couplinginteraction between the magnetically hard and soft phases in theribbon materials.
An analytical approach to the design of electrodes in high-power, fast-transverse-flow CO2 lasers
Abstract Usually, the design of the electrodes of fast-transverse-flow CO 2 lasers relies more on experimental data than on theoretical analysis. Traditional systems sustain a stable, high-power discharge but the current distribution generates a peaked, non-uniform small-signal-gain pattern. We present a theoretical model suitable for the design of electrodes that achieves a quasi uniform gain distribution. The analysis, based on a two-temperature model and the gas-transport equations, computes the electron density that supports a flat gain pattern. Combining the desired electron density with the electron-balance equations, the model determines the required electric field. The results were used to design a new set of electrodes for a home-made fast transverse flow CO 2 laser. A stable, large volume discharge ( 4 × 8 × 90 cm 3 ) with very good uniformity was obtained. The resulting gain distribution was registered in a bi-dimensional map. The peak gain rose from 1.2 m - 1 , attained with the old electrode set, to 1.6 m - 1 with the new one and the gain showed a homogeneous profile.