X-ray magnetic circular dichroism study on ferromagnetic Pd nanoparticles

An x-ray magnetic circular dichroism (XMCD) experiment was performed for freestanding Pd nanoparticles which were prepared in a high purity atmosphere and showed ferromagnetism. We observed the XMCD signal at Pd M2,3 absorption edges of nanoparticles. This is clear experimental evidence of ferromagnetic moment in pure Pd. Using the sum rules, the ratio of orbital to spin magnetic moments mL/mS of ~0.1 was obtained. In the x-ray absorption spectrum, the intensities of white lines increased in Pd nanoparticles relative to the bulk. This shows the increase in the number of unoccupied 4d states nh which can contribute to the appearance of ferromagnetism in Pd.