TY - CPAPER
KW - Nanostructured materials
KW - Phase transitions
KW - Fourier transform infrared spectroscopy
KW - Ferroelectric materials
KW - Phonons
KW - Permittivity
KW - Lead compounds
KW - Thermal effects
KW - Natural frequencies
KW - Routers
KW - Frequency ranges
KW - Mode softening
KW - Optical modes
AU - D Wolpert
AU - W Cox
AU - J Cerne
AU - A Markelz
AU - T Zhao
AU - Ramamoorthy Ramesh
AU - Romanowicz M
AB - We present measurements of the mode softening behavior for PbZr 0.5Ti0.5O3 (PZT(50)) thin films using terahertz time domain spectroscopy (TTDS). The films were grown using pulsed laser deposition (PLD) techniques on silicon substrates to study how reduced size affects the mode softening behavior. At room temperature two modes are observed at 1.1 THz (37 cm-1) and at 2.3 THz (77 cm-1). As the temperature is increased toward Tc we do not see strong mode softening, but rather a spectral weight transfer from the high frequency mode to the low frequency mode. This absence of mode softening is more dramatic than that reported by other investigators[1]. We will discuss the possible sources for this discrepancy. These results suggest a change in lattice dynamics for nanoscale ferroelectric films that may be highly dependent on the sample preparation technique.
BT - 2003 Nanotechnology Conference and Trade Show - Nanotech 2003
LA - eng
N1 - cited By 0
N2 - We present measurements of the mode softening behavior for PbZr 0.5Ti0.5O3 (PZT(50)) thin films using terahertz time domain spectroscopy (TTDS). The films were grown using pulsed laser deposition (PLD) techniques on silicon substrates to study how reduced size affects the mode softening behavior. At room temperature two modes are observed at 1.1 THz (37 cm-1) and at 2.3 THz (77 cm-1). As the temperature is increased toward Tc we do not see strong mode softening, but rather a spectral weight transfer from the high frequency mode to the low frequency mode. This absence of mode softening is more dramatic than that reported by other investigators[1]. We will discuss the possible sources for this discrepancy. These results suggest a change in lattice dynamics for nanoscale ferroelectric films that may be highly dependent on the sample preparation technique.
PY - 2003
SN - 0972842209
SP - 76
EP - 79
T2 - 2003 Nanotechnology Conference and Trade Show - Nanotech 2003
T3 - 2003 Nanotechnology Conference and Trade Show - Nanotech 2003
TI - Finite size effects in ferroelectric nanosystems: Absence of mode softening
VL - 2
ER -