The strain or the electrostriction produced by the application of electric field is proportional to the square of electric polarization. So reversing the electric field will not change the strain. Piezoelectricity on the other hand is linearly proportional to the polarization. The electrostriction is the general property of all insulators whereas piezoelectricity is confined or restricted only to 21 non-centric crystal classes. Similarly magnetostriction is also proportional to the square of the mangnetization.
The strain or the electrostriction produced by the application of electric field is proportional to the square of electric polarization. So reversing the electric field will not change the strain. Piezoelectricity on the other hand is linearly proportional to the polarization. The electrostriction is the general property of all insulators whereas piezoelectricity is confined or restricted only to 21 non-centric crystal classes. Similarly magnetostriction is also proportional to the square of the mangnetization.
Of course your question about the physical mechanisms behind these two effects are more involved and intricate and certainly depends on the material. I shall come back to it if I find more time.
Electrostriction is the broader effect, with grad E^2 is not zero, it is capable to cause mechanical stress in solid dielectric and scalar pressure in liquid dielectrics.
I attached the file, where electrostriction is discussed.
Thanks all for the answers! I would like to have more explanation with example if possible.In which materials which one will dominate and also in which both would be present? The definitions above told are given in books also. I am looking for more explanation and difference between two.
I work on dielectrics more specifically on PMN-PT and wanna understand physics behind two.
In a simple way, the intrinsic physical mechanism is common for the both phenomena, i.e. electric field -> microscopic polarization(s) -> microscopic alignment(s) -> macroscopic strain. It is the symmetry (e.g. disposition of cations and anions in the lattice) makes the difference in terms of the final result.
Vikhnin et al. have provided two mechanism of electrostriction of relaxor ferroelectric of the type of lead magnesium niobate (PMN). (1) The first one is based on the interaction of the soft-lattice polarization and the lattice distortion with the charge transfer fluctuations and with the active ion displacements for the localized Nb-O-Nb and O-Nb-O triads in the disordered relaxor state. (2) The second mechanism is due to the effect of simultaneous interaction of quasilocal vibrations with the soft lattice polarization with lattice distortions. The quasi-local Mg/Ti-O streching modes in PMN and lead zinc niobate (PZN) are involved. For the details read the relevant papers.
Hi everybody
Actually i have one question regarding the result of the Electrostriction and polarization effect.
So when we apply and electric field on a dielectric material the ions of the molecules inside the material is reoriented according to the electric field so in that view what is the difference between the polarization and Electrostriction?
is polarization part of Electrostriction as in the second the we have material dimensions deformation?
Hani, yes. One remark: we may consider various mechanisms/contributions (e.g. polarization of chemical bondings), so a more careful formulation may be as follows. An electric field induces both electric charge displacement (polarization) and mechanical displacement (strain) in a material . In non-ferroelectric materials these processes are reversible; in ferroelectrics these processes may develop irreversible switching of polarization and strain (hysteresis)..
How does electrostriction lead to the electrostrictive force,and hence the deformation?What is the mechanism?
How accurate is the reversal rate to the normal state once the material is strained? Are there any limitations? It would be very helpful if someone could emphasize that.
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