ABSTRACT
The classical understanding of spin glass (SG) behavior is associated with the formation of spin clusters. However, experimental signatures of the spin state—particularly the discrepancy between the characteristic temperatures of the magnetic heat capacity and magnetic susceptibility—are not explained by this picture. We approach the problem from a material-oriented perspective by controlling collective spin behavior through the engineering of chemical disorders. We utilize the ZnFe₂O₄ spinel as a chemical platform, which hosts a pyrochlore sublattice that allows for spin frustration. By establishing a feedback loop between synthesis parameters and crystals quality we create a methodology for controlling chemical disorders [1]. That allows us to reveal the long-range AFM ground state in the ZnFe2O4, previously obscured by excessive level of chemical disorders [2]. We further induce a predominant type of disorder in the system, spin dilution on a pyrochlore sublattice in Zn(Fe,Ga)2O4 [3]. By comparing magnetic responses across different temporal and spatial scales, we identify three distinct types of spin behavior in the system: long-, short-range order, and individual spins. While the characteristic temperature of the heat capacity coincides with the onset of spin correlation length, revealed by neutron diffuse scattering technique, the magnetic susceptibility reflects the freezing of uncorrelated spins. Our work provides a new perspective into the nature of spin glass in real materials, attributing the origin of the state to individual spin, rather than spin clusters.
[1] Dronova et al. PNAS 119, e2208748119 (2022)
[2] Dronova et al. Phys. Rev. B 109, 064421 (2024),
[3] Dronova et al. arXiv:2507.07783 (2025).
BIOGRAPHY
Ms. Dronova is a physicist specializing in condensed matter physics, with a focus on magnetic materials and quantum phenomena. She has been pursuing her Ph.D. at the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan since September 2020, with an expected completion in 2025. At OIST, she is a member of the Electronic and Quantum Magnetism Unit, conducting research on topics such as temporal and spatial separations in spin glass and short-range order, three-dimensional checkerboard spin structures on breathing pyrochlore lattices and inversion disorder in stoichiometric spinel magnets. Her work has been published in journals like PNAS and ACS.
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