Measurement of a Pauli and Orbital Paramagnetic State in Bulk Gold Using X-Ray Magnetic Circular Dichroism Spectroscopy

We show that bulk gold (Au) exhibits temperature-independent paramagnetism in an external magnetic field by x-ray magnetic circular dichroism spectroscopy at the Au L₂ and L₃ edges. Using the sum-rule analysis, we obtained a magnetic moment of 1.3×10^-4μ_B/atom in an external magnetic field of 10 T and a paramagnetic susceptibility of 8.9×10^-6 for the 5d orbit. The induced paramagnetism in bulk Au is characterized by a large (≈30%) orbital contribution. This orbital component was retained even when Au atoms formed nanoparticles, playing an important role in stabilizing the spontaneous spin polarization in the Au nanoparticles.