Thermal enhancement of the antiferromagnetic exchange coupling between Fe epilayers separated by a crystalline ZnSe spacer

J. Varalda (1) , J. Milano (2) , A. J. A. De Oliveira , E. M. Kakuno , I. Mazzaro , D. H. Mosca , L. B. Steren , M. Eddrief (3) , M. Marangolo (3) , D. Demaille (3) , Victor H. Etgens (3)

1 IMPMC - Institut de minéralogie et de physique des milieux condensés
2 Centro Atómico Bariloche [Argentine]
3 INSP - Institut des Nanosciences de Paris

We provide evidence for the existence of an antiferromagnetic coupling between iron epilayers separated by a wedge-like ZnSe crystalline semiconductor by magnetometric and ferromagnetic resonance experiments. The coupling strength of 46 mu J m(-2) for t(ZnSe) = 25 angstrom is strongly reduced as the barrier thickness is increased. The coupling increases linearly with temperature from 5 to 300 K, with a 5.5 x 10(-9) J m(-2) K-1 rate. Thermally induced effective exchange coupling mediated by spin-dependent tunnelling of electrons via localized mid-gap defect states in the ZnSe spacer layer appears to be the most plausible mechanism to induce the antiferromagnetic coupling.

Domaines: Matière Condensée [cond-mat]

J. Varalda, J. Milano, A. J. A. De Oliveira, E. M. Kakuno, I. Mazzaro, et al.. Thermal enhancement of the antiferromagnetic exchange coupling between Fe epilayers separated by a crystalline ZnSe spacer. Journal of Physics: Condensed Matter, 2006, 18 (39), pp.9105-9118. ⟨10.1088/0953-8984/18/39/036⟩. ⟨hal-01293053⟩