We observe the appearance of a phonon near the lock-in temperature in orthorhombic REMnO3 (RE denotes rare earth) (RE: Lu and Ho) and anomalous phonon hardening in orthorhombic LuMnO3. The anomalous phonon occurs at the onset of spontaneous polarization. No such changes were found in incommensurate orthorhombic DyMnO3. These observations directly reveal different electric polarization mechanisms in the E-type and incommensurate-type orthorhombic REMnO3.
Bibliographical noteFunding Information:
This research was funded by DOE Grant Nos. DE-FG02-07ER46402 (NJIT) and DE-FG02-07ER46382 (Rutgers). The U2A beam line at the National Synchrotron Light Source is supported by COMPRES, the Consortium for Materials Properties Research in Earth Sciences under NSF Cooperative Agreement No. EAR01-35554, U.S. Department of Energy (DOE-BES and NNSA/CDAC). The use of the NSLS at Brookhaven National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)