Abstract
Direct engineering of material properties through exploitation of spin, phonon, and charge-coupled degrees of freedom is an active area of development in materials science. However, the relative contribution of the competing orders to controlling the desired behavior is challenging to decipher. In particular, the independent role of phonons, magnons, and electrons, quasiparticle coupling, and relative contributions to the phase transition free energy largely remain unexplored, especially for magnetic phase transitions. Here, we study the lattice and magnetic dynamics of biferroic yttrium orthochromite using Raman, infrared, and inelastic neutron spectroscopy techniques, supporting our experimental results with first-principles lattice dynamics and spin-wave simulations across the antiferromagnetic transition at TN ∼ 138 K. Spectroscopy data and simulations together with the heat capacity (Cp) measurements, allow us to quantify individual entropic contributions from phonons (0.01 ± 0.01kB atom-1), dilational (0.03 ± 0.01kB atom-1), and magnons (0.11 ± 0.01kB atom-1) across TN. High-resolution phonon measurements conducted in a magnetic field show that anomalous T-dependence of phonon energies across TN originates from magnetoelastic coupling. Phonon scattering is primarily governed by the phonon-phonon coupling, with little contribution from magnon-phonon coupling, short-range spin correlations, or magnetostriction effects; a conclusion further supported by our thermal conductivity measurements conducted up to 14 T, and phenomenological modeling.
| Original language | English |
|---|---|
| Article number | 125702 |
| Journal | Journal of Physics Condensed Matter |
| Volume | 33 |
| Issue number | 12 |
| DOIs | |
| State | Published - Mar 23 2021 |
Funding
APR acknowledges the financial support from IRCC-IITB. NB and DB thanks the financial support from BRNS-DAE under the Project Nos. 58/14/30/2019-BRNS/11117, and MHRD-STARS under the Project No. STARS/APR2019/PS/345/FS. The simulations were performed at the SPACETIME super-computing facility at IITB. Experiments at the ISIS Neutron and Muon Source were supported by a beamtime allocation RB1990348 from the Science and Technology Facilities Council. Authors thank the Department of Science and Technology, India (SR/NM/Z-07/2015) for the access to the experimental facility and financial support to carryout the experiment, and Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) for managing the project. UGC-DAE CSR, Indore is acknowledged for extending their Raman spectroscopy facility. Work at ORNL supported in part by the U.S. Department of Energy under contract number DE-AC05-00OR22725. ∗ Authors to whom any correspondence should be addressed. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).
| Funders | Funder number |
|---|---|
| BRNS-DAE | 58/14/30/2019-BRNS/11117 |
| IRCC-IITB | |
| ISIS | RB1990348 |
| MHRD-STARS | STARS/APR2019/PS/345/FS |
| U.S. Department of Energy | DE-AC05-00OR22725 |
| Oak Ridge National Laboratory | |
| Science and Technology Facilities Council | |
| Department of Science and Technology, Ministry of Science and Technology, India | SR/NM/Z-07/2015 |
| Jawaharlal Nehru Centre for Advanced Scientific Research |
Keywords
- Density functional theory
- Magnetoelastic coupling
- Magnetoelectrics
- Multiferroics
- Neutron scattering
- Thermal conductivity
- Thermodynamics