Abstract
We present a detailed study of the local atomic and magnetic structure of the type-I multiferroic perovskite system (Sr,Ba)(Mn,Ti)O3 using x-ray and neutron pair distribution function (PDF) analysis, polarized neutron scattering, and muon spin relaxation (μSR) techniques. The atomic PDF analysis reveals widespread nanoscale tetragonal distortions of the crystal structure even in the paraelectric phase with average cubic symmetry, corresponding to incipient ferroelectricity in the local structure. Magnetic PDF analysis, polarized neutron scattering, and μSR likewise confirm the presence of short-range antiferromagnetic correlations in the paramagnetic state, which grow in magnitude as the temperature approaches the magnetic transition. We show that these short-range magnetic correlations coincide with a reduction of the tetragonal (i.e., ferroelectric) distortion in the average structure, suggesting that short-range magnetism can play an important role in magnetoelectric and/or magnetostructural phenomena even without genuine long-range magnetic order. The reduction of the tetragonal distortion scales linearly with the local magnetic order parameter, pointing to spontaneous linear magnetoelectric coupling in this system. These findings provide greater insight into the multiferroic properties of (Sr,Ba)(Mn,Ti)O3 and demonstrate the importance of investigating the local atomic and magnetic structure to gain a deeper understanding of the intertwined degrees of freedom in multiferroics.
| Original language | English |
|---|---|
| Article number | 024423 |
| Journal | Physical Review B |
| Volume | 109 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 1 2024 |
Funding
We thank M. Abeykoon for help with the x-ray PDF experiment, along with M. Everett, J. Liu, and C. Li for help with the neutron PDF experiment. For assistance with the experiment, we thank G. Morris, S. Wu, S. Haley, and E. Zappala. B.A.F. and B.J. were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (DOE-BES) through Award No. DE-SC0021134. C.Z.S. was supported by the College of Physical and Mathematical Sciences at Brigham Young University. Work in the Materials Science Division at Argonne National Laboratory (materials synthesis, magnetic characterization and preliminary x-ray diffraction) was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. This research used beamline 28-ID-1 of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. This study used resources at the Spallation Neutron Source (SNS), a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.
| Funders | Funder number |
|---|---|
| College of Physical and Mathematical Sciences at Brigham Young University | |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | DE-SC0021134 |
| Argonne National Laboratory | |
| Brookhaven National Laboratory | DE-SC0012704 |
| Division of Materials Sciences and Engineering |