scholarly journals In situ Transmission Electron Microscopy Studies of Electric-field-induced Phenomena in Ferroelectrics

2005 ◽  
Vol 20 (7) ◽  
pp. 1641-1653 ◽  
Author(s):  
Xiaoli Tan ◽  
Hui He ◽  
Jian-Ku Shang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Domain Wall ◽  
Electric Field ◽  
Single Crystal ◽  
Electric Fields ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Transmission Electron ◽  
High Electric Fields

High electric fields were delivered to specimens during imaging in the transmission electron microscopy (TEM) chamber to reveal details of electric field-induced phenomena in ferroelectric oxides. These include the polarization switching in nanometer-sized ferroelectric domains and the grain boundary cavitation in a commercial lead zirconate titanate (PZT) polycrystalline ceramic, the domain wall fracture in a Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystal, and the transformation of incommensurate modulations in Pb0.99Nb0.02[(Zr1−xSnx)1−yTiy]0.98O3 (PZST100x/100y/2) polycrystalline ceramics. In the PZT ceramic, a cavitation process was uncovered for the electric field-induced intergranular fracture. In the ferroelectric single crystal, a preexisting crack was observed to deflect and to follow a 90° domain wall, indicating the presence of severe incompatible piezoelectric strains at thedomain wall. In the antiferroelectric PZST ceramics, the electric field-induced antiferroelectric-to-ferroelectric phase transformation was accompanied with the disappearance of incommensurate modulations.

Ultrastructural changes in Staphylococcus aureus treated with pulsed electric fields / Cambios ultraestructurales en Staphylococcus aureus sometida a campos eléctricos pulsantes

1997 ◽  
Vol 3 (2) ◽  
pp. 113-121 ◽  
Author(s):  
U.R. Pothakamury ◽  
G.V. Barbosa-Cánovas ◽  
B.G. Swanson ◽  
K.D. Spence
Keyword(s):  
Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Electric Field ◽  
Electric Fields ◽  
Untreated Control ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
Treat Ment

Early stationary phase cells of Staphylococcus aureus were inoculated into a model food, simulated milk ultrafiltrate (SMUF) and subjected to 16, 32, and 64 pulses at electric field intensities of 20, 40 and 60 kV/cm at 13 °C. In addition temperatures of 20, 25 and 30 °C were also tested with 32 pulses and an electric field of 60 kV/cm. The temperature of the SMUF increased by 1-2 ° C at the end of the 64 pulses. Cells subjected to 64 pulses at 20, 40 and 60 kV/cm were observed for ultrastructural changes using scanning and transmission electron microscopy techniques. The cell surface was rough after treatment with electric field when observed by scanning electron microscopy (SEM). The cell wall was broken, and the cytoplasmic contents were leaking out of the cell after exposure to 64 pulses at 60 kV/cm when observed by transmission electron microscopy (TEM). The breaking of the cell wall is an indication of electro-mechanical breakdown of the cell. The increase in inactivation with an increase in the electric field strength can be related to the increase in the damage to the cells. Cells subjected to 32 pulses at 60 kV/cm and 13, 20 or 25 °C were compared microscopically with the untreated control cells. Cells subjected to heat treat ment (10 min, at 66 °C) were compared with electric field-treated and untreated control cells. Although important changes were observed in the protoplast, no cell wall breakdown was observed in heat-treated cells when compared to the electric field-treated cells. This result indi cates a different mechanism of inactivation of cells with heat treatment.

X-ray diffraction and high-resolution transmission electron microscopy study on A-site ordering of lanthanum-modified lead zirconate titanate relaxor

1995 ◽  
Vol 10 (7) ◽  
pp. 1582-1584 ◽  
Author(s):  
Fei Fang ◽  
Xiaowen Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Lead Zirconate Titanate ◽  
Microscopy Study ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconate Titanate ◽  
Transmission Electron

The ordering behavior of La-modified lead zirconate titanate relaxor (PLZT 9/65/35) was investigated by use of an x-ray diffractometer (XRD) and high-resolution transmission electron microscopy (HRTEM). It was shown that a {h + 1/2, k + 1/2, 0}-type superlattice exists both in the x-ray diffraction pattern and selected area electron diffraction (SAED) image. High-resolution electron micrographs further demonstrated the existence of the superlattice and exposed the ordered and disordered regions in the lattice level. A model referring to an A-site body-centered pseudo-cubic superstructure was proposed.

De-aging of Fe-doped lead-zirconate-titanate ceramics by electric field cycling: 180°- vs. non-180° domain wall processes

2012 ◽  
Vol 112 (3) ◽  
pp. 034103 ◽  
Author(s):  
Julia Glaum ◽  
Yuri A. Genenko ◽  
Hans Kungl ◽  
Ljubomira Ana Schmitt ◽  
Torsten Granzow
Keyword(s):  
Domain Wall ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Zirconate Titanate ◽  
Field Cycling ◽  
Titanate Ceramics
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