scholarly journals Superconducting size effect in thin films under electric field: Mean-field self-consistent model

2019 ◽  
Vol 100 (22) ◽  
Author(s):  
P. Virtanen ◽  
A. Braggio ◽  
F. Giazotto
Keyword(s):  
Thin Films ◽  
Electric Field ◽  
Size Effect ◽  
Mean Field ◽  
Consistent Model ◽  
Self Consistent

Elastic Property Estimation in Polycrystalline Films with Crystallographic Texture and Grain Shape

1995 ◽  
Vol 403 ◽  
Author(s):  
B. C. Hendrix ◽  
L. G. Yu ◽  
K. W. Xu ◽  
J. W. He
Keyword(s):  
Thin Films ◽  
Elastic Constants ◽  
Crystallographic Texture ◽  
Grain Shape ◽  
Elastic Anisotropy ◽  
Polycrystalline Films ◽  
Property Estimation ◽  
Bulge Testing ◽  
Consistent Model ◽  
Self Consistent

AbstractAlthough methods of measuring the elastic properties of thin films have made great advances with the use of bulge testing of membranes, deflection of micromachined beams, and nanoindentation, most results are still being compared to either isotropic or single crystal elastic constants, neither of which are, in general, appropriate for textured polycrystalline films. This paper uses recent results of a self-consistent model (after Krbner and Kneer) which calculates the elastic anisotropy arising from crystallographic texture and which has been extended to predict the anisotropy resulting from grain shape. These results are compared to the various Voigt, Reuss, and Hill approximations that are appropriate for different crystallographic textures. The accuracies of the different models are evaluated in terms of their ability to predict the biaxial modulus and indentation compliance that are most commonly measured in thin films.

A self-consistent polycrystal model for the spontaneous polarization of ferroelectric ceramics

2006 ◽  
Vol 462 (2070) ◽  
pp. 1763-1789 ◽  
Author(s):  
Y Su ◽  
G.J Weng
Keyword(s):  
Curie Temperature ◽  
Electric Field ◽  
Spontaneous Polarization ◽  
Mixture Theory ◽  
Temperature Shift ◽  
Dielectric Constants ◽  
Ferroelectric Ceramics ◽  
Consistent Model ◽  
Self Consistent ◽  
Polycrystalline Ceramic

Motivated by the observation that the spontaneous polarization process of a ferroelectric polycrystal under the influence of a superimposed stress and/or electric field involves heterogeneous evolution of the ferroelectric phase among its constituent grains, a self-consistent electromechanical model is developed to determine the effective behaviour of the polycrystalline ceramic from such a heterogeneous electromechanical state. We start out from consideration of a micromechanics-based thermodynamic process to establish the kinetic equation of the crystallite and use it to evaluate the evolution of its ferroelectric domain. Then together with the Curie–Weiss law for the dielectric constants of the tetragonal phase, a dual-phase mixture theory is adopted to determine the change of its electromechanical moduli as temperature cools down below its Curie point. The overall property of the polycrystal is subsequently calculated by the self-consistent model through orientational average over its constituent grains. This two-level micromechanics model is applied to examine the shift of Curie temperature and evolution of the effective electromechanical moduli of a BaTiO 3 ceramic under cooling. The calculated results show that its Curie temperature decreases with increasing hydrostatic pressure, but increases with a superimposed axial compression or a biased electric field. The predicted temperature shift and change of the dielectric constants are found to be consistent with experimental observations.

THEORY AND SELF-CONSISTENT MODEL OF DUST-DRIVEN WINDS

2002 ◽  
Vol 5 ◽  
pp. 65-65
Author(s):  
S. Liberatore ◽  
J.-P.J. Lafon ◽  
N. Berruyer
Keyword(s):  
Consistent Model ◽  
Self Consistent
Sign in / Sign up

Export Citation Format

Share Document