Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9834103 | Journal of Magnetism and Magnetic Materials | 2005 | 8 Pages |
Abstract
Magnetostrictive alloys with a wide operating temperature range from â80 to 150 °C were developed by changing the Tb/Dy ratio of TbxDy1âxFe2 from 0.3/0.7 to 0.36/0.64 and Co partly substituting for Fe. The structure, Curie temperature, AC susceptibility, magnetization, magnetocrystalline anisotropy constant K1 and magnetostriction of Tb0.36Dy0.64(Fe1âyCoy)2 (y=0.0, 0.1, 0.2) alloys were investigated. It was found that the matrix of Tb0.36Dy0.64(Fe1âyCoy)2 alloys keeps the MgCu2-type cubic Laves structure with a small amount of R-rich phase. A small amount of R2(Fe,Co) phase was also detected when y=0.2. The Curie temperature Tc of Tb0.36Dy0.64(Fe1âyCoy)2 alloys is higher than Tb0.3Dy0.7Fe2 and increases drastically with increasing Co content from 387.1 °C for Tb0.36Dy0.64Fe2 to 416.7 °C for Tb0.36Dy0.64(Fe0.9Co0.1)2 and 433.3 °C for Tb0.36Dy0.64(Fe0.8Co0.2)2. The spin reorientation temperature Tr decreases from â12 °C for Tb0.3Dy0.7Fe2 to â94 °C for Tb0.36Dy0.64Fe2. It increases slightly with increasing Co content. The magnetocrystalline anisotropy coefficient K1 of Tb0.36Dy0.64(Fe1âyCoy)2 alloys is greater than Tb0.3Dy0.7Fe2 but decreases with increasing Co content. The saturation magnetization Ms of Co-doped alloys is lower than that of Tb0.3Dy0.7Fe2 and decreases with increasing Co content. The magnetostriction of Tb0.3Dy0.7Fe2 and Tb0.36Dy0.64(Fe1âyCoy)2 alloys was examined against applied magnetic field up to 5 kOe in the temperature range from â80 to 150 °C.The temperature coefficient of magnetostriction (Îλ/ÎT) of Tb0.3Dy0.7Fe2 and Tb0.36Dy0.64(Fe1âyCoy)2 alloys was also calculated by linearly simulating the magnetostriction-temperature curve, showing that the absolute value of Îλ/ÎT at 5 kOe magnetic field is 1.17 ppm/°C for y=0.1 and 1.35 ppm/°C for y=0.2, smaller than that of Co free samples, which is 2.43 ppm/°C for Tb0.36Dy0.64Fe2.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Tianyu Ma, Chengbao Jiang, Xiang Xu, Hu Zhang, Huibin Xu,