Dresden 2003 – scientific programme

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MA: Magnetismus

MA 29: Mikro- und nanostrukturierte Materialien II

MA 29.2: Talk

Friday, March 28, 2003, 11:00–11:15, HSZ/03

Magnetic and Structural Properties of the Arrays of Magnetic Nanowires and Layer of Cobalt — •Hamid R. Khan^1,2 and Kerstin Petrikowski¹ — ¹FEM, Abt. Materialphysik, 73525 Schwaebisch Gmuend,BRD — ²Department of Physics, University of Tennessee, Knoxville, TN. U.S.A.

Arrays of magnetic nanowires possess very different magnetic properties compared to bulk materials (1). The diameter, interwire distance, and the length of the nanowires effect the structural and magnetic properties. Nanomagnet arrays are interesting for applications .as high density storage media as well as for the fundamental understanding. Arrays of nanowires of 18, 30 and 78 nm diameters and different interwire distances and lengths are prepared by electrodeposition of Co in the pores of anodic alumina. A Co layer is also deposited on a copper substrate. Nanowire arrays and the layer show a hcp structure and different preffered orientations.. Arrays show perpendicular magnetic anisotropy due to the shape anisotropy and crystallographic orientation effects whereas the layer shows an inplane anisotropy. The Coercivity Hc(Perp.) and Mr/Ms decrease exponentially with increasing nanowire diameter.. An enhancement in Hc(Perp).is observed at 77 K. Analysis of the magnetic data of nanowire arrays in relation to the composition, crystallographic structure, diameter and interwire distance and a comparison with the bulk layer will be described. 1. H.R. Khan and K. Petrikowski, Journal of Magnetism and Magnetic Materials 249(2002) 458 -461. This work was supported by the Bundesministerium für Wirtschaft, Grant no. AiF 11429N.