Lattice dynamics and structural correlations in antiferromagnet SrLaCoNbO6 double perovskite
Abstract
We report a detailed temperature-dependent Raman spectroscopy and Co K-edge extended x-ray absorption fine structure (EXAFS) study of the insulating antiferromagnetic double perovskite SrLaCoNbO6. Interestingly, pronounced changes in the phonon frequencies, linewidths, and intensities are observed around 60~K, well above the long-range antiferromagnetic ordering temperature, TN ≈ 15~K. These anomalies indicate a modification of the lattice dynamics that may involve local structural distortions, short-range magnetic correlations, or an interplay between them. Additional changes in both high- and low-energy Raman modes are detected near 160--180~K via variations in phonon intensities and linewidths, together with changes in the Fano asymmetry of selected low-energy modes. The asymmetric line shapes of these modes are well described phenomenologically by Fano profiles and indicate coupling of the discrete phonons to an underlying continuum, whose possible microscopic origins are discussed. Moreover, the EXAFS analysis reveals correlated changes in bond distances and Debye--Waller factors around the Co ions near 60~K and 160~K, indicating subtle local structural distortions at temperatures corresponding to the Raman anomalies. The combined Raman and EXAFS results therefore demonstrate a close correlation between anomalous lattice dynamics and local structural evolution in SrLaCoNbO6.
Related
- Disentangling octahedral distortion and symmetry breaking in the ordered double perovskite SrLaCoNbO6
- Proximate spin liquid ground state arising from competing stripy and 120◦ spin correlations in the triangular quantum antiferromagnet ErMgGaO4
- Quasi-2D Perovskite Photonic Crystals for Single-Mode Lasing via Synergistic Material and Structural Optimization by Nanoimprint Lithography
- Collective Coordinate Dynamics of Antiferromagnet: Gravity by Quantum Metric
- High-quality (PEA) 2 (FA)Pb 2 I 7 Ruddlesden–Popper hybrid perovskite single crystals: growth, structural and optical properties
BibTeX
@misc{kumar2026lattice,
title = {{Lattice dynamics and structural correlations in antiferromagnet SrLaCoNbO$_6$ double perovskite}},
author = {Ajay Kumar and Clemens Ulrich and Rajendra S. Dhaka},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.07630},
eprint = {2607.07630},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.07630},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Lattice dynamics and structural correlations in antiferromagnet SrLaCoNbO_6 double perovskite
AU - Ajay Kumar
AU - Clemens Ulrich
AU - Rajendra S. Dhaka
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2607.07630
UR - https://arxiv.org/abs/2607.07630
AB - We report a detailed temperature-dependent Raman spectroscopy and Co K-edge extended x-ray absorption fine structure (EXAFS) study of the insulating antiferromagnetic double perovskite SrLaCoNbO_6. Interestingly, pronounced changes in the phonon frequencies, linewidths, and intensities are observed around 60~K, well above the long-range antiferromagnetic ordering temperature, T_N ≈ 15~K. These anomalies indicate a modification of the lattice dynamics that may involve local structural distortions, short-range magnetic correlations, or an interplay between them. Additional changes in both high- and low-energy Raman modes are detected near 160--180~K via variations in phonon intensities and linewidths, together with changes in the Fano asymmetry of selected low-energy modes. The asymmetric line shapes of these modes are well described phenomenologically by Fano profiles and indicate coupling of the discrete phonons to an underlying continuum, whose possible microscopic origins are discussed. Moreover, the EXAFS analysis reveals correlated changes in bond distances and Debye--Waller factors around the Co ions near 60~K and 160~K, indicating subtle local structural distortions at temperatures corresponding to the Raman anomalies. The combined Raman and EXAFS results therefore demonstrate a close correlation between anomalous lattice dynamics and local structural evolution in SrLaCoNbO_6.
ER -