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

VARALDA, J.; JULIAN MILANO; OLIVEIRA, A. J. A.; KAKUNO, E. M.; MAZZARO, I.; MOSCA, D. H.; STEREN, L. B.; DEMAILLE, D.; EDDRIEF, M.; MARANGOLO, M.

JOURNAL OF PHYSICS CONDENSED MATTER

INSTITUTE OF PHYSICS PUBLISHING

Año: 2006 vol. 18 p. 9105 - 9105

0953-8984

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 ƒÊJ m−2 for tZnSe = 25 ?‹A is strongly reduced as the barrier thickness is increased. The coupling increases linearly with temperature from 5 to 300 K, with a 5.5 ?~ 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.ƒÊJ m−2 for tZnSe = 25 ?‹A is strongly reduced as the barrier thickness is increased. The coupling increases linearly with temperature from 5 to 300 K, with a 5.5 ?~ 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..5 ?~ 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.