Thank you so much professor for this well established lecture over ceramics and their properties related to orientation of groups and thus the dielectric constants which prove to be the stepping stone for millon dollar industries. I just had a question sir if i may. Q. Sir as you described about how electric field is responsible for the orientation of the groups which were randomly oriented earlier but upon application and increasing electric field they oriented themselves having a net dipole. Sir if we take the case of piezoelectrics which happend to produce electricfield upon application of stress so can they be used for the same effect so that all we provide is mechanical stress in order to produce ceramics with high dielectric constants ?
Is it possible that the domain boundaries match the grain boundaries in a polycrystalline ferroelectric material or these two concepts don't have anything to do with each other? In other words, is the orientation of the dipole within each unit cell independent of the orientation of the unit cells in a grain, for e.g., or are the dipoles oriented along the c-axis of the cells? If the dipoles are pointing in a different direction than the c-axis, doesn't that mean there is some sort of shearing in the lattice?
Domain boundaries and grain size are two completely diff aspects for the generation of ceramics with high dielectric constant. The grain size if in accordance with the temp dependence of ceramics , wherea as domain size or group size or the we may say the time taken by preffered domain to grow under increasing application field in order to allign the dipoles parallel to each other and thus produce a net dipole.
Yes the orientation of dipoles inside the group are paralled to each other but groups are oriented randomly so innately there is no net dipole unless electri field is started to be applied
There is a shearing in the lattice to make it a non linear structure in other words else than cubic because unless and untill there is no distortion in the lattice there wont be dipoles there thus our starting condition pf pervoskite structure always having dipole moments comes at flaw. Thus , yes there is shearing in the lattice
you gave the definition of a ferroelectric as a material having a spontaneous polarization even in the absence of electric field, so that when you ploted the hesterisis you have corresponded Ps= 0 to E = 0 ? there are any explication?
I read from a book[piezoeletric materials and devices]. it says that the ferroelectric material possesses a property of reversible polarization so that the spontaneous polarization can be reversed by the applying an external electric field. and I think the hysteresis just want to show the very initial state of the material at the origin.
il parle sur la polarisation resultatnt qui est egale à zero mais la polarisation spontanée veut dire que les moments dipolaires des domaines ferroelectroques ne sont pas nuls ils sont orientés, chaque domaine ets orienté selon une direction dont la resultatnt donne P=0
If you see the hysterisis graph again at E=0 , The value of Polarizability is a value at Y -Axis with a dotted line which depicts that unless a negative bias wont be applied further polarizability wont be 0. At E=0 , Ps=/0
Fantastic lecture. The professor has a well organized presentation that makes the subject matter very approachable. Thanks!
very well explained thank you for sharing such high quality lecture
wow i found that this class is very important and the professor also present is very essyly
Thank you professor for sharing the knowledge 🙏 best wishes
Thank you so much professor for this well established lecture over ceramics and their properties related to orientation of groups and thus the dielectric constants which prove to be the stepping stone for millon dollar industries.
I just had a question sir if i may.
Q.
Sir as you described about how electric field is responsible for the orientation of the groups which were randomly oriented earlier but upon application and increasing electric field they oriented themselves having a net dipole.
Sir if we take the case of piezoelectrics which happend to produce electricfield upon application of stress so can they be used for the same effect so that all we provide is mechanical stress in order to produce ceramics with high dielectric constants ?
sir can we calculate piezoelectric sensitivity using PE loop
God bless you professor, Thank you for your great explanation!
Is it possible that the domain boundaries match the grain boundaries in a polycrystalline ferroelectric material or these two concepts don't have anything to do with each other? In other words, is the orientation of the dipole within each unit cell independent of the orientation of the unit cells in a grain, for e.g., or are the dipoles oriented along the c-axis of the cells? If the dipoles are pointing in a different direction than the c-axis, doesn't that mean there is some sort of shearing in the lattice?
Domain boundaries and grain size are two completely diff aspects for the generation of ceramics with high dielectric constant.
The grain size if in accordance with the temp dependence of ceramics , wherea as domain size or group size or the we may say the time taken by preffered domain to grow under increasing application field in order to allign the dipoles parallel to each other and thus produce a net dipole.
Yes the orientation of dipoles inside the group are paralled to each other but groups are oriented randomly so innately there is no net dipole unless electri field is started to be applied
There is a shearing in the lattice to make it a non linear structure in other words else than cubic because unless and untill there is no distortion in the lattice there wont be dipoles there thus our starting condition pf pervoskite structure always having dipole moments comes at flaw. Thus , yes there is shearing in the lattice
Elucidate explanation about the topics
52:00 ceramic
you gave the definition of a ferroelectric as a material having a spontaneous polarization even in the absence of electric field, so that when you ploted the hesterisis you have corresponded Ps= 0 to E = 0 ? there are any explication?
I read from a book[piezoeletric materials and devices]. it says that the ferroelectric material possesses a property of reversible polarization so that the spontaneous polarization can be reversed by the applying an external electric field. and I think the hysteresis just want to show the very initial state of the material at the origin.
il parle sur la polarisation resultatnt qui est egale à zero mais la polarisation spontanée veut dire que les moments dipolaires des domaines ferroelectroques ne sont pas nuls ils sont orientés, chaque domaine ets orienté selon une direction dont la resultatnt donne P=0
If you see the hysterisis graph again at E=0 , The value of Polarizability is a value at Y -Axis with a dotted line which depicts that unless a negative bias wont be applied further polarizability wont be 0.
At E=0 , Ps=/0
WTF