A new soft X-ray magnetic circular dichroism facility at the BSRF beamline 4B7B

Abstract

X-ray magnetic circular dichroism (XMCD) has become an important and powerful tool because it allows the study of material properties in combination with elemental specificity, chemical state specificity, and magnetic specificity. A new soft X-ray magnetic circular dichroism apparatus has been developed at the Beijing Synchrotron Radiation Facility (BSRF).The apparatus combines three experimental conditions: ultra-high-vacuum environment, moderate magnetic fields and in-situ sample preparation to measure the absorption signal. We designed a C type dipole electromagnet that provides magnetic fields up to 0.5T in parallel (or anti-parallel) direction relative to the incoming X-ray beam. The performances of the electromagnet are measured and the results show good agreement with the simulation ones.Following film grown in situ by evaporation methods, XMCD measurements are performed.Combined polarization corrections, the magnetic moments of the Fe and Co films determined by sum rules are consistent with other theoretical predictions and experimental measurements.

Applications of Field-reversal and Angle-dependent XMCD Techniques to Mn-based Diluted Magnetic Materials

“…By using the sum rule to the data set, we can obtain the spin and orbit moments at 0, 45 and 60 degree, and then fit the orbit moments by the equation for the Fe element in the bilayer. Compared it to our previous results in reference [9], orb m  is slightly larger than the orbit moments of bulk Fe, and the orb m is 7.6 times larger which indicate the presence of a huge magnetic anisotropy in the bilayer.…”

“…A new soft X-ray XMCD setup has been designed and constructed in our recent work [9] at the 4B7B beamline, which is a bending magnet beamline at Beijing Synchrotron Radiation Facility (BSRF), equipped with a varied-line-spacing plane grating monochromator. Demonstration XMCD experiments in ferromagnetic 3d transition metals (Fe, Co and Ni) films and ultrathin films were performed.…”

Molecular Chirality and Its Monitoring by Ultrafast X-ray Pulses

“…X-ray FELs are less common but produce ultrashort high brilliance beams (few femtoseconds or even attosecond) particularly suitable for ultrafast time-resolved nonlinear experiments. The improvement and development of dedicated beamlines with accurate polarization control of X-rays at synchrotrons − and FELs − are making chiral techniques increasingly available to a broader range of experiments. We further note that many beamlines built for XMCD at synchrotrons can be used for XCD measurements.…”