Abstract
We combined synchrotron-based infrared absorbance and Raman scattering spectroscopies with diamond anvil cell techniques and a symmetry analysis to explore the properties of multiferroic (NH4)2FeCl5·H2O under extreme pressure-temperature conditions. Compression-induced splitting of the Fe-Cl stretching, Cl-Fe-Cl and Cl-Fe-O bending, and NH4+ librational modes defines two structural phase transitions, and a group-subgroup analysis reveals space group sequences that vary depending upon proximity to the unexpectedly wide order-disorder transition. We bring these findings together with prior high-field work to develop the pressure-temperature-magnetic field phase diagram uncovering competing polar, chiral, and magnetic phases in this system.
| Original language | English |
|---|---|
| Pages (from-to) | 11021-11029 |
| Number of pages | 9 |
| Journal | Inorganic Chemistry |
| Volume | 63 |
| Issue number | 24 |
| DOIs | |
| State | Published - Jun 17 2024 |
Funding
Research at the University of Tennessee is supported by Chemical Structure and Dynamics, Division of Chemistry, National Science Foundation (CHM-2342425). Work at ORNL is funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, Condensed Matter Experiment and Theory Programs. Work at the National Synchrotron Light Source II at Brookhaven National Laboratory is funded by the Department of Energy (DE-AC98-06CH10886). Use of the 22-IR-1 beamline is supported by the National Science Foundation─Earth Sciences via SEES: Synchrotron Earth and Environmental Science (EAR – 2223273) and CDAC (DE-NA0003975). We thank J. Fernandez-Baca and R. S. Fishman for useful conversations.