Spatially homogeneous ferromagnetism below the enhanced Curie temperature in EuO_1-x thin films

Pedro M. S. Monteiro, Peter J. Baker, Adrian Ionescu, Crispin H. W. Barnes, Zaher Salman, Andreas Suter, Thomas Prokscha, and Sean Langridge

Accepted Thursday May 2, 2013

We have used low energy implanted muons as a volume sensitive probe of the magnetic properties of EuO1-x thin films. We find that static and homogeneous magnetic order persists up to the elevated TC in the doped samples and the muon signal displays the double dome feature also observed in the sample magnetization. Our results appear incompatible with either the magnetic phase separation or bound magnetic polaron descriptions previously suggested to explain the elevated TC, but are compatible with an RKKY-like interaction mediating magnetic interactions above 69 K.