Study On The Preparation And Properties Of Light Rare-earth Magnetostrictive Materials And MnBiAl Thin Film

In this work, the preparation and properties of magnetostrictive material and MnBiAl thin film are studied.On account of the solidification character of rare earth alloys, the zone melting is improved by putting the alloys prepared by arc-melting into the quartz tube, then melting. The technological parameters such as the diameter of quartz tube, the dimension of materials and parameters in zone melt are analyzed. Ingots of Cex(Tbo.27Dyo.73)i-xFe2 and Pro.i5TbxDyo.85-xFe2 alloys is prepared by arc-melting in a cold copper crucible under an argon atmosphere protection. The lattice constant, courier temperature and magnetostrictin of Cex(Tbo.27Dyo.73)i-xFe2 and Pro.i5TbxDyo.8s-xFe2 alloys is studied. It is shown that, in Cex(Tbo.27Dyo.73)i-xFe2 alloys, the valence of Ce is moved to +3 with the Ce increasing, the magnetostriction of Cex(Tbo.2?Dyo.73)i-xFe2 alloys is decreased with Ce increasing. In Pro.i5TbxDyo.g5-xFe2 alloys, due to the Pr as substitute for Tb, the point of the lowest magneto-crystalline anisotropy is shifted to 0.3, the magnetostriction of Pro.i5Tbo.3Dyo.5sFe2 alloys is SOOppm higher than Tbo.27Dyo.73Fe2 alloys at 20KOe. The Pro.i5Tbo.3Dyo.5sFe2 stick orienting by <110> is prepared by improving zone melting. Although the dimension is only $ 7.9 X 30mm, the more bigger and oriented by <211> or <111> will be prepared by adjusting technological parameters.The Terfenol-D and Pro.i5TbojDyo.55Fe2 composite is prepared by polymer-bonding method. The influence of the proportion of binder and compaction pressure on the density, resistivity and magnetostriction of the bonded composites have been investigated. It was found that the sample density increases with the increasing compaction pressure, while the resistivity decrease with the increasing compaction pressure. The compaction pressure between 48MPa and 148MPa has a little effect on the magnetostriction. The highest density and the low resistivity and the best magnetostriction in a composite rod were obtained when the proportion of binder to powders' weight is 4:100. The large magnetostriction of 1186xlO"6 at 450KA/m for Terfenol-D composite with the applied compressive stress of lOMPa and magnetostriction of 900x10"6 at 900KA/m for Pro.isTbojDyo.ssFea composite are obtained. The magnetostriction of 350ppm for the bonded composite with Al as binder at 900KA/m is obtained.MnBiAl thin film orienting by <002> is prepared by sputtering. The structure of Bi film and MnBiAl film is investigated. It is shown that Bi film on SrTiC>3 substrate orienting in <100> is mainly oriented in <003>, while Bi film on glass substrate is disoriented. The study of the Mn:Bi influence on the structure of MnBiAl film shows that ,on the base of the same Al content , only the specimen with Mn:Bi 1:0.92 possesses single phase structure of MnBiorienting in <002>. With the whole thickness fixed, the structure of sole layer specimen [Bi/Al/Mn] is more integral than that of double layers specimen [Bi/Al/Mn/Bi/Al/Mn]. The measurement of MnBiAl torque at low temperature shows that MnBiAl film possesses a perpendicular magnetic anisotropy with decreasing temperature down to 80K.