Structure and magnetic properties of Cu-10wt% Co alloys processed by twin roller melt spinning

被引:4
作者
Fabietti, L. M. [1 ]
Urreta, S. E. [1 ]
机构
[1] Univ Nacl Cordoba, Fac Matemat Astron & Fis, RA-5000 Cordoba, Argentina
关键词
CoCu alloys; twin roller melt spinning; giant magnetoresistance;
D O I
10.1016/j.physb.2007.04.041
中图分类号
O469 [凝聚态物理学];
学科分类号
070205 ;
摘要
Nanostructured magnetic Cu- 10 wt% Co alloys have been processed by ultra rapid solidification, in a twin roller melt spinning device. This solidification method (two wheels) is known to promote a more uniform microstructure as compared with that resulting in single wheel devices. The structural properties of ribbons processed at tangential wheel speeds of 5 and 23 m/s, in the as-cast condition and after a heat treatment of I h at 923 K, are investigated by X-ray diffraction techniques; the magnetic properties are also characterized by M-H loop measurements and the electric resistance measured as a function of the applied magnetic field at 300 K. The M-H loops can be described by the sum of a superparamagnetic like component involving small, interacting clusters of pure Co, and a soft ferromagnetic contribution which is likely to arise in the matrix. The X-ray spectra are consistent with a Cu matrix exhibiting a spinodal like Co concentration profile even in specimens in the as-cast condition. Isothermal annealing above 873 K results in the formation of larger Co clusters, in an improvement of the nominal coercivity and also leads to a higher polarization at a maximum field of 1. 5 T. On the other hand, magneto resistance effects are observed in as-cast samples solidified at 23 m/s but not in the specimen cooled at 5 m/s nor in those heat treated for I It at 923 K. (C) 2007 Elsevier B.V. All rights reserved.
引用
收藏
页码:348 / 351
页数:4
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