Distortion mode anomalies in bulk PrNiO3: Illustrating the potential of symmetry-adapted distortion mode analysis for the study of phase transitions
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Institut des Molécules et Matériaux du Mans (IMMM) - UMR 6283 CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans, France
- Institut Laue Langevin, 71 avenue des Martyrs, CS 20156 -38042 Grenoble CEDEX 9, France
DOI10.24435/materialscloud:2019.0084/v2 (version v2, submitted on 14 December 2019)
How to cite this entry
Dariusz J. Gawryluk, Y. Maximilian Klein, Tian Shang, Denis Sheptyakov, Lukas Keller, Nicola Casati, Philippe Lacorre, Maria Teresa Fernandez-Diaz, Juan Rodriguez-Carvajal, Marisa Medarde, Distortion mode anomalies in bulk PrNiO3: Illustrating the potential of symmetry-adapted distortion mode analysis for the study of phase transitions, Materials Cloud Archive (2019), doi: 10.24435/materialscloud:2019.0084/v2.
The origin of the metal-to-insulator transition (MIT) in RNiO3 perovskites with R = trivalent 4 f ion has challenged the condensed matter research community for almost three decades. A drawback for progress in this direction has been the lack of studies combining physical properties and accurate structural data covering the full nickelate phase diagram. Here we focus on a small region close to the itinerant limit (R = Pr, 1.5 K < T < 300 K), where we investigate the gap opening and the simultaneous emergence of charge order in PrNiO3. We combine electrical resistivity, magnetization, and heat capacity measurements with high-resolution neutron and synchrotron x-ray powder diffraction data that, in contrast to previous studies, we analyze in terms of symmetry-adapted distortion modes. Such analysis allow us to identify the contribution of the different modes to the global distortion in a broad temperature range. Moreover, it shows that the structural changes at the MIT, traditionally described in terms of the evolution of the interatomic distances and angles, appear as abrupt increases of all nonzero mode amplitudes at TMIT = TN ∼ 130 K accompanied by the appearance of new modes below this temperature. A further interesting observation is the existence of a nearly perfect linear correlation between the amplitude of the breathing mode associated to the charge order and the staggered magnetization below the MIT. Our data also uncover a previously unnoticed anomaly at T ∗ ∼ 60 K (∼0.4 × TMIT), clearly visible in the electrical resistivity, lattice parameters and some mode amplitudes. Since phase coexistence is only observed in a small temperature region around TMIT (∼±10 K), these observations suggest the existence of a hidden symmetry in the insulating phase. We discuss some possible origins, among them the theoretically predicted existence of polar distortions induced by the noncentrosymmetric magnetic order [Perez-Mato et al., J. Phys.: Condens. Matter 28, 286001 (2016); Giovanetti et al., Phys. Rev. Lett. 103, 156401 (2009)].
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|35.4 MiB||Experimental data files (text or excel format).|
|3.5 KiB||Amplimodes input (SG Pbnm), text format|
|4.9 KiB||Amplimodes input (SG P21/n), text format|
|31.9 KiB||Detailed output (Amplimodes fits), docx format|
|40.8 KiB||Detailed output (Atomic coordinate fits), text format|
|681 Bytes||Contents of the folder "Data_files.zip" , text format|
14 December 2019 [This version]
02 December 2019