H. Jaffres et al., MAGNETIC DOMAINS AND MAGNETIZATION REVERSAL IN EPITAXIAL FE LAYERS PATTERNED BY THE ATOMIC SAW METHOD, Journal of applied physics, 84(8), 1998, pp. 4375-4383
We present a study of the magnetic domains structure and the magnetiza
tion reversal in systems of stripes and dots patterned on Fe films by
the atomic saw method. Continuous epitaxial 50 and 20 Angstrom Fe film
s have been grown by molecular beam epitaxy deposition method, then by
applying strain on MgO monocrystalline substrate and controlling the
dislocation slipping, micronic iron stripes and dots have been obtaine
d. For the system of 1.4 mu m wide stripes characterized by a strong u
niaxial magnetic anisotropy (H-a = 1500 Oe) resulting from a uniaxial
relaxation of Fe lattice parameter, large magnetic domains have been o
bserved by Kerr microscopy imaging. This structure is not directly cor
related to the geometry of ribbons. It reveals the strong influence of
the mutual dipolar coupling leading to a quasi-collective magnetizati
on reversal. In contrast, Kerr microscopy observations done on samples
structured into 1-3 mu m dots show that the domain wall propagation i
s hindered by the net of orthogonal steps generated by the process. Th
e domain architecture is then directly twinned to the geometry of dots
. Both dot mean size and effective size dispersion which is imposed by
the dipolar field seem to be the two relevant parameters that govern
the two steps magnetization reversal. Calculations of coupling dipolar
field are done showing its strong influence upon the magnetization re
versal in the stripes case. (C) 1998 American Institute of Physics. [S
0021-8979(98)07119-9].