We used x-ray magnetic circular dichroism (XMCD) to obtain element specific magnetization curves. The most common way measuring XMCD in the soft x-ray region is total electron yield (TEY), because of the easy experimental setup and high signal-to-noise ratio compared to fluorescence yield. Surprisingly TEY was used only marginally for magnetization curves in the past. We show that the major problem using field dependent TEY is the complex current behavior as a function of applied magnetic fields, which directly results in corresponding normalization problems. We developed a simple but effective normalization method in combination with symmetry arguments to obtain magnetization curves using TEY as a probe for XMCD. Quick (2–6 min) and high quality data could be extracted in a wide range of high magnetic fields. In comparison to fluorescence yield hysteresis loops, those measurements could be easily done at synchrotron bending magnet beamlines and no high brilliant undulator sources and/or long measurement times are necessary. As an example we compare hysteresis loops of the colossal magnetoresistance compound La0.7Ca0.3MnO3 measured in situ by XMCD at the Mn L3 edge and conventional ex situ measurements.

Evidence for short range orbital order in paramagnetic insulating (Al,V) The local structure of (Al0.06V0.94)2O3 in the paramagnetic insulating (PI) and antiferromagnetically ordered insulating (AFI) phase has been investigated using hard and soft x-ray absorption techniques. It is shown that: 1) on a local scale, the symmetry of the vanadium sites in both the PI and the AFI phase is the same; and 2) the vanadium 3d -oxygen 2p hybridization, as gauged by the oxygen 1s absorption edge, is the same for both phases, but distinctly different from the paramagnetic metallic phase of pure V2O3. These findings can be understood in the context of a recently proposed model which relates the long range monoclinic distortion of the antiferromagnetically ordered state to orbital ordering, if orbital short range order in the PI phase is assumed. The measured anisotropy of the x-ray absorption spectra is discussed in relation to spin-polarized density functional calculations.

No abstract

No abstract