Element specific XMCD hysteresis loops of iron oxides

Full text: X-ray magnetic circular dichroism (XMCD) is one of the most useful types of measurement to investigate magnetic properties using synchrotron radiation X-rays. XMCD is measured at the X-ray absorption edge of a specified element in a sample, which enables element-selective measurement. The intensity of XMCD is proportional to the mean magnetic moment projected onto the direction of the incident X-ray, and the sign reflects the direction of the probed moment relative to that of the total magnetization. Due to contributions of Fe³⁺ occupying octahedral sites and Fe³⁺ occupying tetrahedral sites in iron oxides are clearly distinguishable in XMCD signal it is possible to obtain hysteresis loops for each iron site. In this work we present XMCD hysteresis loops taken at Fe L-edge on maghemite and Zn ferrites nanoparticles and thin films in total electron yield at LNLS (PGM beamline). The results will be compared with hysteresis loops taken by a vibrating sample magnetometer in the same conditions. (author)