in a spintronic device.
Here, we demonstrate an antiferromagnetic coupling
and exchange bias in Fe/(Ga,Mn)As bilayer ﬁlms, by
combining element-speciﬁc XMCD measurements and
bulk-sensitive superconducting quantum interference de-
vice (SQUID) magnetometry. As with previous studies
of FM metal/FM semiconductor bilayers4,5 (and in con-
trast to AFM coupled FM metal/FM metal exchange bias
structures10,11) the layers are in direct contact without
a non-magnetic spacer in between. We distinguish in-
terface and bulk (Ga,Mn)As layers that are respectively
strongly and weakly antiferromagnetically coupled to the
Fe overlayer. In agreement with Ref.7, the interface layer
remains polarized at room temperature.
The Fe and (Ga,Mn)As layers of the present study
were both grown by molecular beam epitaxy in the same
ultra-high vacuum system, in order to ensure a clean in-
terface between them. The (Ga,Mn)As layer of thickness
10 to 50 nm was deposited on a GaAs(001) substrate
at a temperature of 260◦C, using previously established
methods3,8. A low Mn concentration of x ≈ 0. 03 was
chosen in order to avoid the formation of compensating
Mn interstitials. The substrate temperature was then
reduced to∼0◦C, before depositing a 2 nm Fe layer,
plus a 2 nm Al capping layer. In-situ reﬂection high
energy electron diﬀraction and ex-situ x-ray reﬂectivity
and diﬀraction measurements conﬁrmed that the layers
are single-crystalline with sub-nm interface roughness.
SQUID magnetometry measurements were performed us-
ing a Quantum Design Magnetic Property Measurement
System. Mn and FeL2,3 x-ray absorption and XMCD