Engineering topics
Gao, P
Publications and source records attributed to Gao, P.
SMARCA3, a Chromatin-Remodeling Factor, Is Required for p11-Dependent Antidepressant Action
Abstract not provided
Phase transitions, phase coexistence, and piezoelectric switching behavior in highly strained BiFeO3 films
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High-pressure Structural Stability of Multiferroic Hexagonal RMnO3 (R=Y Ho Lu)
Structural changes in RMnO{sub 3} (R = Y, Ho, Lu) under high pressure were examined by synchrotron x-ray diffraction methods at room temperature. Compression occurs more readily in the ab plane than along the c axis. With increased pressure, a pressure-induced hexagonal to orthorhombic phase transition was observed starting at {approx}22 GPa for Lu(Y)MnO{sub 3}. When the pressure is increased to 35 GPa, a small volume fraction of Lu(Y)MnO{sub 3} is converted to the orthorhombic phase and the orthorhombic phase is maintained on pressure release. High-pressure infrared absorption spectroscopy and Mn K-edge near-edge x-ray absorption spectroscopy confirm that the hexagonal P6{sub 3}cm structure is stable below {approx}20 GPa and the environment around the Mn ion is not changed. Shifts in the unoccupied p-band density of states with pressure are observed in the Mn K-edge spectra. A schematic pressure-temperature phase diagram is given for the small ion RMnO{sub 3} system.
Observation of Anomalous Phonons in Orthorhombic Rare-earth Manganites
We observe the appearance of a phonon near the lock-in temperature in orthorhombic REMnO{sub 3} (RE denotes rare earth) (RE: Lu and Ho) and anomalous phonon hardening in orthorhombic LuMnO{sub 3}. The anomalous phonon occurs at the onset of spontaneous polarization. No such changes were found in incommensurate orthorhombic DyMnO{sub 3}. These observations directly reveal different electric polarization mechanisms in the E-type and incommensurate-type orthorhombic REMnO{sub 3}.
High-pressure structural stability of multiferroic hexagonal RMnO3 (R=Y, Ho, Lu)
Structural changes in RMnO{sub 3} (R= Y, Ho, Lu) under high pressure were examined by synchrotron x-ray diffraction methods at room temperature. Compression occurs more readily in the ab plane than along the c axis. With increased pressure, a pressure-induced hexagonal to orthorhombic phase transition was observed starting at {approx}22 GPa for Lu(Y)MnO{sub 3}. When the pressure is increased to 35 GPa, a small volume fraction of Lu(Y)MnO{sub 3} is converted to the orthorhombic phase and the orthorhombic phase is maintained on pressure release. High-pressure infrared absorption spectroscopy and Mn K-edge near-edge x-ray absorption spectroscopy confirm that the hexagonal P6{sub 3}cm structure is stable below {approx}20 GPa and the environment around the Mn ion is not changed. Shifts in the unoccupied p-band density of states with pressure are observed in the Mn K-edge spectra. A schematic pressure-temperature phase diagram is given for the small ion RMnO{sub 3} system.