31 research outputs found
Substrate-induced antiferromagnetism of an Fe monolayer on the Ir(001) surface
We present detailed ab initio study of structural and magnetic stability of a
Fe-monolayer on the fcc(001) surface of iridium. The Fe-monolayer has a strong
tendency to order antiferromagnetically for the true relaxed geometry. On the
contrary an unrelaxed Fe/Ir(001) sample has a ferromagnetic ground state. The
antiferromagnetism is thus stabilized by the decreased Fe-Ir layer spacing in
striking contrast to the recently experimentally observed antiferromagnetism of
the Fe/W(001) system which exists also for an ideal bulk-truncated, unrelaxed
geometry. The calculated layer relaxations for Fe/Ir(001) agree reasonably well
with recent experimental LEED data. The present study centers around the
evaluation of pair exchange interactions between Fe-atoms in the Fe-overlayer
as a function of the Fe/Ir interlayer distance which allows for a detailed
understanding of the antiferromagnetism of a Fe/Ir(001) overlayer. Furthermore,
our calculations indicate that the nature of the true ground state could be
more complex and display a spin spiral-like rather than a
c(2x2)-antiferromagnetic order. Finally, the magnetic stability of the Fe
monolayer on the Ir(001) surface is compared to the closely related Fe/Rh(001)
system.Comment: 8 pages, 4 figure