Admixture of excited states and ground states of aEu3+ion inEu3Fe5O12by means of magnetic circular dichroism

Abstract

The soft x-ray absorption spectroscopy (XAS) and magnetic circular dichroism (MCD) have been measured around the ${M}_{4,5}$ edges at $T=20$ and 300 K in order to investigate the electronic states of ${\mathrm{Eu}}^{3+}$ ions in ${\mathrm{Eu}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$. We found a structure in both the XAS and MCD spectra, which was not observed at $T=20\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, on the lower energy side of the ${M}_{5}$ edge at room temperature. By using atomic model calculations, the origin of the structure is assumed to be due to the thermal effect for the degree of admixture of the excited states ($J=1$, 2) and ground states $(J=0)$ of ${\mathrm{Eu}}^{3+}$. Developing the linear response model to investigate the magnetic moment obtained from the experimental spectra, we conclude that the thermal excited states of ${\mathrm{Eu}}^{3+}$ ions is the linear combination between $J=0$, 1, and 2 and the magnetic-field-excited state is the quantum-mechanically mixed state of the ground and excited states.