Comparison of patterning of highly ordered CoPt alloys with perpendicular anisotropy using two methods: ion etching and ion irradiation

Madjid Abes ,  Julien Vénuat ,  Mircea V. Rastei ,  Alain Carvalho ,  Guy Schmerber ,  Jean-Pierre Bucher ,  Aziz Dinia ,  Eric Beaurepaire ,  Véronique Pierron-Bohnes 

Institut de Physique et Chimie des Materiaux de Strasbourg, UMR7504, CNRS - ULP, 23, rue du Loess, BP 43, Strasbourg CEDEX 2 67034, France

Abstract

CoPt alloy layers were prepared by molecular beam epitaxy, deposited directly on a MgO(001) substrate. These layers had the L10 tetragonal structure, ordered in the growth direction with an easy magnetization direction perpendicular to the layer plane and a 100 percent remanence. The layers were nanostructured using two different methods:

A) A network of dots were classically realized by electron beam lithography and ion etching. Whereas the continuous layers had a labyrinthine magnetic structure after perpendicular demagnetization, all the dots are single domains with randomly distributed up and down magnetization.

B) Ionic irradiation was used to magnetically pattern a CoPt alloy film, using a mask to protect arrays of CoPt dots during a ionic irradiation. The unprotected regions became disordered and magnetically soft, whereas the protected regions remain magnetically hard. This spatially selective irradiation provides a spatial distribution of magnetic anisotropy and hence of the magnetization direction, perpendicular to plane in the ordered zones and in-plane in the disordered zones. The interest of this method is that the film recovers its initial roughness after elimination of the mask which is promising for the data storage applications.
 

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Presentation: Oral at E-MRS Fall Meeting 2006, Symposium A, by Véronique Pierron-Bohnes
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-13 15:51
Revised:   2009-06-07 00:44