Ferromagnetic hcp chromium in Cr/Ru(0001) superlattices.
We report the first observation of a weak ferromagnetic state of Cr in Cr/Ru(0001) superlattices, based on magnetic hysteresis and corroborated by x-ray magnetic circular dichroism at the CrL(2,3) edges. In situ reflection high-energy electron diffraction, x-ray diffraction, and Cr K-edge polarized x-ray absorption investigations have shown that the Cr layers thinner than 8 angstroms adopt a slightly distorted hcp structure, accompanied by a large atomic volume expansion of up to 14% compared to the bcc packing volume. The expanded hcp structure clearly induces the observed ferromagnetism, in agreement with theory.
Albrecht
M
M
Department of Physics, University of Konstanz, D-78457 Konstanz, Germany. manfred.albrecht@uni-konstanz.de
Maret
M
M
Kohler
J
J
Gilles
B
B
Poinsot
R
R
Hazemann
J L
JL
Tonnerre
J M
JM
Teodorescu
C
C
Bucher
E
E