Hexagonal arrays of submicronic ferromagnetic wires obtained by multiple extrusion of bulk samples

A new method of producing regular arrays of submicronic semi-infinite wires is briefly described here. The technique is based on the multiple extrusio n of composite wires, known as the bronze route, generally used for the pre paration of superconducting wires. This method has been applied to the prep aration of ferromagnetic wires (Fe, Ni) embedded in a Cu matrix. Using this technique wires diameters can be continuously varied between 1 mm and 10 n m. A clear shape induced anisotropy field is observed, associated for small diameters to coercive forces as high as 400 Oe in the case of Fe. The magn etization processes are described in the framework of the classical microma gnetic theory of magnetization reversal. (C) 1999 American Institute of Phy sics. [S0021-8979(99)66008-X].