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著者
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Shang-Hsien Hsieh, Surajit Ghosh, Yu-Hui Liang, Hsiao-Tsu Wang, Chao-Hung Du, Jau-Wern Chiou, Chun-Ming Wu, Chin-Wei Wang, Yu-Cheng Shao, Jeng-Lung Chen, Chih-Wen Pao, Huang-Ming Tsai, Ting-Shan Chan, Wen-Bin Wu, Hong-Ji Lin, Jyh-Fu Lee, Asokan Kandasami, Way-Faung Pong |
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摘要
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This work studies the correlation between noncollinear spin orientation and lattice distortion in 𝑋𝑌-like spin-glass (SG) Ni0.4Mn0.6TiO3 (NMTO) using neutron diffraction and synchrotron-radiation-based spectroscopic techniques such as resonant inelastic x-ray scattering (RIXS), x-ray absorption spectroscopy, and x-ray magnetic circular dichroism (XMCD). The neutron study reveals a shorter spin-spin correlation length along the 𝒄 axis than in the 𝑋𝑌-plane, which is typical of 𝑋𝑌-like SG. It also reveals that the NiTiO3 matrix dominates the shaping of the low-temperature complex magnetic structure of NMTO. A local lattice distortion in the form of a large increase in the nearest-neighbor Ni-O bond length along the 𝒄 axis was observed from temperature-dependent extended x-ray absorption fine-structure measurements close to the SG transition temperature, 𝑇SG. The Ni 𝐿3-edge RIXS spectra at around 𝑇SG indicate a possible magnon excitation with various 𝑑−𝑑 interactions and charge-transfer excitation. The Ni 𝐿3,2-edge XMCD measurement shows ferromagnetic-/ferrimagneticlike behavior at the temperature near 𝑇SG, closely matching the opening of hysteresis curves that are recorded below 𝑇SG. These findings compellingly demonstrate that at low temperature, Ni2+ ions in the 𝑋𝑌-plane of NMTO exhibit a noncollinear spin alignment, that facilitates Dzyaloshinskii-Moriya-type exchange interactions, elucidating the complex spin dynamics of this SG system. |
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