What Materials Cannot Use the Electric Potential Energy Law?

[stefano colom]

my professor has explained Electric potential energy Law U=∫D*E above all the space. he said you can not use for some kind of materials. l can 't remember if they are Ferroelectricity or piezoelectric materials. then can you say to me the reason too? thank you

 

[Naty1]

I'm guessing he might have been alluding to the hysteresis effect of ferromagentic materials.
more here:http://en.wikipedia.org/wiki/Ferroelectricity

 

[Darwin123]

I'm guessing he might have been alluding to the hysteresis effect of ferromagentic materials.
more here:http://en.wikipedia.org/wiki/Ferroelectricity

There is a hysteresis effect in ferroelectric materials, too.

 

[stefano colom]

but why couldn't l use for the ferroelectricity materials

 

[Meir Achuz]

The derivation of the D.E form requires that the relation between D and E be linear.
It is not for ferroelectric materials.