Dielectric constants of the alkaline‐earth chalcogenides

1978 ◽  
Vol 49 (8) ◽  
pp. 4503-4505 ◽  
Author(s):  
S. C. Goyal
Keyword(s):  
Alkaline Earth ◽  
Dielectric Constants

Low‐Frequency Dielectric Constants of the Alkaline Earth Fluorides by the Method of Substitution

1971 ◽  
Vol 42 (6) ◽  
pp. 2216-2219 ◽  
Author(s):  
Carl Andeen ◽  
John Fontanella ◽  
Donald Schuele
Keyword(s):  
Alkaline Earth ◽  
Low Frequency ◽  
Dielectric Constants

Devitrification and dielectric properties of (Na2O,BaO)–Nb2O5–SiO2 and (K2O,SrO)–Nb2O5–SiO2 glass–ceramics

2007 ◽  
Vol 22 (7) ◽  
pp. 1996-2003 ◽  
Author(s):  
Fei Peng ◽  
Robert F. Speyer ◽  
Wesley Hackenberger
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Alkaline Earth ◽  
Amorphous Matrix ◽  
Glass Ceramics ◽  
Dielectric Constants ◽  
Sio2 Glass ◽  
Increasing Temperature

(Na2O,BaO)–Nb2O5–SiO2 and (K2O,SrO)–Nb2O5–SiO2 glass ribbons with varying proportions of alkali and alkaline earth were formed using roller quenching. (Na2O,BaO)–Nb2O5–SiO2 glasses of compositions devitrified to form Ba2NaNb5O15 (in the form of ∼80 nm crystallites in an amorphous matrix) yielded frequency-stable dielectric constants of ∼250 and losses of ∼0.05. Such low losses and frequency stabilities were also observed from (K2O,SrO)–Nb2O5–SiO2 glasses of compositions forming predominantly KSr2Nb5O6 (∼30 nm crystals), yielding dielectric constants of ∼400. Both optimized compositions showed moderate decreases in dielectric constant with increasing temperature.

Electron microscopy studies of PZT ferroelectric film capacitor structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1364-1365
Author(s):  
V. Kaushik ◽  
P. Maniar ◽  
J. Olowolafe ◽  
R. Jones ◽  
A. Campbell ◽  
...  
Keyword(s):  
Electric Fields ◽  
Sol Gel ◽  
Ferroelectric Material ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Lead Zirconium Titanate ◽  
Si Substrate ◽  
Film Capacitor ◽  
Pzt Films ◽  
High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

The need of electron microscopy in the study of domains and domain walls in ferroelectrics

1994 ◽  
Vol 52 ◽  
pp. 550-551
Author(s):  
Wenwu Cao
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
High Mobility ◽  
Continuum Theory ◽  
Polarization Vector ◽  
Ferroelectric Materials ◽  
Dielectric Constants ◽  
Nonlocal Coupling ◽  
Cubic Symmetry ◽  
Gradient Energy

Domain structures play a key role in determining the physical properties of ferroelectric materials. The formation of these ferroelectric domains and domain walls are determined by the intrinsic nonlinearity and the nonlocal coupling of the polarization. Analogous to soliton excitations, domain walls can have high mobility when the domain wall energy is high. The domain wall can be describes by a continuum theory owning to the long range nature of the dipole-dipole interactions in ferroelectrics. The simplest form for the Landau energy is the so called ϕ model which can be used to describe a second order phase transition from a cubic prototype,where Pi (i =1, 2, 3) are the components of polarization vector, α's are the linear and nonlinear dielectric constants. In order to take into account the nonlocal coupling, a gradient energy should be included, for cubic symmetry the gradient energy is given by,

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