Hello, In some papers, they mentions the critical electric field or critical field in ferroelectric ceramics. what is the difference betweeen "critical electric field" and "critical field" ? ,or these are the same term ？ what is critical electric field?
could anyone help me explain them? or recommend some papers ?
Thanks a lot in advances.
Dear Xiangjian Wang,
Please refer the following links. You may get clarification about the topic.
https://en.wikipedia.org/wiki/Superconductivity
http://textofvideo.nptel.iitm.ac.in/113105015/lec24.pdf
http://www.jetp.ac.ru/cgi-bin/dn/e_067_06_1235.pdf
http://nptel.ac.in/courses/113104005/88
thanks a lot . I read some papers. I got some information about that.
Dear Xiangjian,
I came very late about two years late. My answer may be useful to the researchers who are interested in this topic.
Ceramic materials behave as insulators so their properties are studied by applying electric field on them and observing their polarization. So, the field here is the electric field.
The critical electric field is the electric field strength to affect electrical breakdown of the material. It is the electric field at which the current in the material increases indefinitely.
Best wishes
Dear Dr.Abdelhalim Zekry Thanks a lot!
I read and check papers and got some informations
The critical electric fields have different explainations at different cases.
as you mentioned that that is one critical electric field of electric breakdown field.
other cases, like the electric field can induce the switching of ferroelectric domain.Also called critical field.
Thanks again.
Best Regards,
Xiangjian Wang
Dear Xiangjian,
as you stated the term "critical electric field" can have several meanings. It depends on the publication you are reading, but " critical field" should mean the same as "critical electric field" in ferroelectrics. It should be clear or deducable from the context.
It might be that some authors state the electric field of switching as the critical electric field but it should be better termed coercive field or switching field. Especially, the electric field to induce switching is frequency dependent and therefore not a single electric field. It should be always connected to the frequency of the observation.
The term "critical electric field" actually describes the electric field of the critical point. This point in the E-T phase diagram is characterized by the critical electric field and the critical temperature. It can be observed for first order ferroelectrics or for some relaxor materials. In both cases it was shown that the critical point is actually a critical end point, which means that at this point in the E-T plane the line of first order transitions terminates into the critical end point where the phase transition is of second order. So the critical end point (and thereby the critical electric field) is a unique electric field for a certain material.
I hope this helped.
All the best
Florian Weyland Thank you very much! You really offer lots of informations to explain "Critical field".
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