Magneto-Structural Coupling Enables Cryogenic Cation Redistribution in a Spinel Oxide
Abstract
Ionic transport in oxides is generally frozen at cryogenic temperatures, where thermal energy lies far below typical cation-migration barriers. Neutron powder diffraction reveals progressive Fe/Mg redistribution between tetrahedral (A) and octahedral (B) sites in the spinel Mg0.5Fe0.5TiFeO4 upon cooling from 200 K to 5 K. A-site Fe occupancy increases toward near completion at 5 K within Rietveld resolution, while Ti remains on the B site. This exchange coincides with complex magnetic correlations rather than a classical thermally activated window. Low-temperature magnetostrictive volume changes indicate strong spin-lattice coupling, but do not identify magnetostriction as the sole thermodynamic driver. Room-temperature high-pressure X-ray diffraction produces the opposite occupancy trend, showing that volume contraction alone cannot explain the cryogenic site exchange. These results point to magneto-structural free-energy minimization as a plausible mechanism for unlocking cryogenic cation mobility in a correlated spinel oxide.
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BibTeX
@misc{han2026magnetostructural,
title = {{Magneto-Structural Coupling Enables Cryogenic Cation Redistribution in a Spinel Oxide}},
author = {Yifeng Han and Yixing Zhao and Yunbo Ou and Feiran Shen and Lunhua He and Ligang Xu and Mingxue Tang and Jared Matteucci and Zexiao Zhang and Xiaoli Ma and Xiaohui Yu and Zheng Deng and Man-Rong Li and Alexandra Navrotsky},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.02368},
eprint = {2609.02368},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.02368},
}
RIS
TY - UNPB
TI - Magneto-Structural Coupling Enables Cryogenic Cation Redistribution in a Spinel Oxide
AU - Yifeng Han
AU - Yixing Zhao
AU - Yunbo Ou
AU - Feiran Shen
AU - Lunhua He
AU - Ligang Xu
AU - Mingxue Tang
AU - Jared Matteucci
AU - Zexiao Zhang
AU - Xiaoli Ma
AU - Xiaohui Yu
AU - Zheng Deng
AU - Man-Rong Li
AU - Alexandra Navrotsky
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2609.02368
UR - https://arxiv.org/abs/2609.02368
AB - Ionic transport in oxides is generally frozen at cryogenic temperatures, where thermal energy lies far below typical cation-migration barriers. Neutron powder diffraction reveals progressive Fe/Mg redistribution between tetrahedral (A) and octahedral (B) sites in the spinel Mg0.5Fe0.5TiFeO4 upon cooling from 200 K to 5 K. A-site Fe occupancy increases toward near completion at 5 K within Rietveld resolution, while Ti remains on the B site. This exchange coincides with complex magnetic correlations rather than a classical thermally activated window. Low-temperature magnetostrictive volume changes indicate strong spin-lattice coupling, but do not identify magnetostriction as the sole thermodynamic driver. Room-temperature high-pressure X-ray diffraction produces the opposite occupancy trend, showing that volume contraction alone cannot explain the cryogenic site exchange. These results point to magneto-structural free-energy minimization as a plausible mechanism for unlocking cryogenic cation mobility in a correlated spinel oxide.
ER -