Linear Dichroism at the Fe L-edge in DyFe3(BO4)3
J. Okamoto1, A. Singh1, H. Y. Huang1, T. C. Huang1, W. B. Wu1, Y. Tanaka2, T. Usui3, T. Kimura4, C. T. Chen1, D. J. Huang1, A. Chainani1*
1Condensed Matter Physics, NSRRC, Hsinchu, Taiwan
2Advanced Photon Technology Div., RIKEN SPring-8 Center, Hyogo, Japan
3Div. of Materials Physics, Osaka University, Osaka, Japan
4Dept. of Advanced Materials Science, Univ. of Tokyo, Chiba, Japan
* Presenter:A. Chainani
The rare-earth iron borate DyFe3(BO4)3 exhibits a first order structural transition at T_s = 285 K, followed by a transition to an antiferromagnetic phase below T_N = 38 K. It exhibits a magneto-electric effect and spin-flop behavior below T_N. Neutron diffraction studies have shown that the Fe-sublattice antiferromagnetic order consists of Fe spins aligned along the c-axis, while recent studies have shown a quadrupole helix chirality setting in below T_s for the Dy and Fe sublattices. In this work, we carry out experiments of Linear dichroism in X-ray absorption spectroscopy (LD-XAS) across the Fe L-edge to study the temperature dependent changes in the electronic structure across T_s and T_N. Our LD-XAS results show clear changes across T_N but negligible changes across T_s. Based on many-body cluster calculations, we discuss the electronic structure of DyFe3(BO4)3 in terms of electronic parameters, namely, the strong on-site Coulomb correlation energy (Udd), the charge-transfer energy (Delta), the Fe-O hybridization strength and the crystal field splitting.

Keywords: X-ray absorption spectroscopy, Linear dichroism, Magneto-electric, Chiral structure