Size effect on magnetism of Fe thin films in Fe/Ir superlattices

S. Andrieu (1) , C. Chatelain , M. Lemine (1) , B. Berche (1) , Ph. Bauer

1 LPM - Laboratoire de physique des matériaux

In ferromagnetic thin films, the Curie temperature variation with the thickness is always considered as continuous when the thickness is varied from $n$ to $n+1$ atomic planes. We show that it is not the case for Fe in Fe/Ir superlattices. For an integer number of atomic planes, a unique magnetic transition is observed by susceptibility measurements, whereas two magnetic transitions are observed for fractional numbers of planes. This behavior is attributed to successive transitions of areas with $n$ and $n+1$ atomic planes, for which the $T_c$\'s are not the same. Indeed, the magnetic correlation length is presumably shorter than the average size of the terraces. Monte carlo simulations are performed to support this explanation.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

S. Andrieu, C. Chatelain, M. Lemine, B. Berche, Ph. Bauer. Size effect on magnetism of Fe thin films in Fe/Ir superlattices. Physical Review Letters, 2001, 86, pp.3883-3886. ⟨10.1103/PhysRevLett.86.3883⟩. ⟨hal-00009479⟩