Imaging microspectroscopy of Ni/Fe/Co/Cu(001) using a photoemission microscope

The magnetic phases of 0-6 atomic monolayers (ML) Ni/0-14 ML Fe/6 ML Co/Cu( 001) trilayer crossed double wedges are studied by the combination of photo electron emission microscopy and X-ray magnetic circular dichroism spectros copy at the Fe L-2,L-3 edges. This microspectroscopic technique allows the extraction of local quantitative magnetic information. The presence of thre e magnetically different thickness regions of Fe with effective spin moment s per atom of 2.5 mu(B) (below approximate to 3.5 ML), 0.7 mu(B) (approxima te to 3.5-11 ML), and 2.0 mu(B) (above approximate to 11 ML) is confirmed. At 7-9 ML thickness, the value of 0.7 mu(B) is consistent with a ferromagne tic Fe surface layer on top of non-ferromagnetic layers. The ratio of orbit al to effective spin moment varies between 0.05 for very thin Fe films and 0.15 for thicker films, if correction of saturation effects is taken into a ccount. Images of the magnetic circular dichroism asymmetry at the Ni and C o L-3 edges show that at 5.5 ML Fe thickness the Ni and Co magnetizations h ave opposite orientations, pointing towards antiferromagnetic coupling acro ss the Fe layer. (C) 2000 Elsevier Science B.V. All rights reserved.