Abstract: High-field X-ray absorption spectroscopies can provide valuable information for paramagnetic materials and antiferromagnetic systems. The effective magnetic moment of BaCoO3 estimated from the magnetic susceptibility is 2.23 μB larger than 1.73 μB expected for low-spin Co4+. The deviation might be attributed to non-zero orbital moment, while the elongation of the CoO6 octahedron would result in the hole occupation of the a1g orbital with m=0. By use of X-ray magnetic circular dichroism (XMCD) combined with theoretical simulations, we found the the hole would occupy at the eg orbital owing to the short distance between Co ions along the c axis which also leads to the finite orbital moment of Co. On the other hand, the antiferromagnetic structure of TbFe3(BO3)4 and the modifications under external magnetic field were detected via X-ray linear dichroism and XMCD. The enhancement of the magnetization in the antiferromagnetic phase can be attributed to not only the flop of the Fe moment but also the increase of the Tb moment.
November 24, 2021 02:20 PM
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Low-temperature high-field X-ray absorption spectroscopies
秦伊瑩教授 Prof. Yi-Ying Chin from Department of Physics, NCCU
@ CCMS/PHYSICS BUILDING R104 (Chin-Pao Yang Lecture Hall)