Using x-ray magnetic circular and linear dichroism techniques, we demonstrate a collinear exchange coupling between an epitaxial antiferromagnet, tetragonal CuMnAs, and an Fe surface layer. A small uncompensated Mn magnetic moment is observed which is antiparallel to the Fe magnetization. The staggered magnetization of the 5 nm thick CuMnAs layer is rotatable under small magnetic fields, due to the interlayer exchange coupling. This allows us to obtain the x-ray magnetic linear dichroism spectra for different crystalline orientations of CuMnAs in the (001) plane. This is a key parameter for enabling the understanding of domain structures in CuMnAs imaged using x-ray magnetic linear dichroism microscopy techniques.

Diamond Light Source Chilton Didcot Oxfordshire OX11 0DE United Kingdom

Faculty of Mathematics and Physics Charles University Ke Karlovu 3 121 16 Praha 2 Czech Republic

Institute of Physics Czech Academy of Sciences Cukrovarnická 10 162 00 Praha 6 Czech Republic

Institute of Physics Czech Academy of Sciences Na Slovance 1999 2 182 21 Praha 8 Czech Republic

Institute of Solid State Physics TU Wien Wiedner Hauptstr 8 1040 Wien Austria

Max Planck Institute for Chemical Physics of Solids 01187 Dresden Germany

School of Physics and Astronomy University of Nottingham Nottingham NG7 2RD United Kingdom

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