1. Dec 5, 2012

### athosanian

hello, I am learning electromagnetism and read the polarization in dielectric. The text book tell me that in linear dielectric exists a simple relation:
P=$\chi$*ε0*E
where $\chi$ is the susceptibility, ε0 is the permittivity of vacuum and E is total electric field in the dielectric. It is noted that E is the total field, namely, applied external field E_0 plus depolarization field E_d in the media.
But when I search this topic on the wiki, I find it says polarization is proportional to the applied external field (link below). So I have a confuse about meaning of E, which is right? I hope any help. Thanks.

http://en.wikipedia.org/wiki/Ferroelectricity

2. Dec 6, 2012