Low frequency magnetic noise in epitaxial antiferromagnetically coupled Fe/Cr multilayers

For antiferromagnetically coupled epitaxial [Fe/Cr(0 0 1)] 10 multilayers we detected a strong enhancement of the magnetism-related electrical noise in the vicinity of the orientation transition between the easy and hard axes. Our measurements are performed at different temperatures and we also identified the noise caused by depinning of domain walls (DWs). We are able to detect and follow in real time the motion of rather extended (of the order of 100 μm ) DWs by comparing the magnetic noise in the presence and absence of a DC transport current, respectively. The presence of large and small (