It , really, causes a pain in the neck while arguing this (one of the best) question asked by a young scholar.

[A]No doubt, both have the prefix “ferro”- meaning iron despite the fact that MOST FERROELECTRIC MATERIALS DO NOT CONTAIN IRON.

{B] The ferromagnetism ( in simple terms) arises by the “In phase alignment” of “infinesimally large aggregates of paramagnetic species” so that their resultant molar magnetic susceptibility{ χM } becomes of the order of 10^5- 10^6 times the susceptility of a single paramagnetic species. In a nut shell, FERROMAGNETISM IS AN IN PHASE ADDITIVE PROPERTY OF PARAMAGNETISM .The parmagnetism arises from both from the “SpinMotion” as well as the “ Orbital Motion” of the “unpaired” electron; both of which couple to give the resultant Magnetic Moment(μeffective) as calculated by applying certain formulas to the {χM}.

[C]The very pertinent question -when there can be present unpaired s-, p-, d- and f – electrons, yet why do the unpaired “d” electrons become so important?

[D]In case of s- bpock elements/ their compounds( alkali/ alkaline earths),there are hardly any compounds which have unpaired electron/s. So they are not expected to exhibit paramagnetism and thus there are no chances of their showing ferromagnetism which can arise only if there are paramagnetic aggregates. As regards to their elemental state, though alkali metals have the outermost configuration ns^1( and one may expect them to be paramagnetic) ,yet EVEN IN THEIR VAPOR FORM, THEY EXIST AS DIMERS and thus do not have any unpaired electron. So neither do the s-block elements/ compounds exhibit paramagnetism nor they are expected to show ferromagnetism.

[E] Considering the f- block elements/ their compounds. The outermost electron enters ENERGETICALLY VERY LOW LYING 4f( lanthanides) or 5f( actinides)[ Antepenultimate{ outermost but second) shell] which are HARDLY AFFECTED ENERGETICALLY on the formation of their compounds. This means that their aggregates RARELY show an IN PHASE ADDITIVE PROPERTY; meaning therbyy that they CAN SHOW PARAMAGNETISM BUT RARELY* SHOW FERROMAGNETISM . So lanthanide/ actinide , very commonly, show paramanetism but hardly show ferromagnetism. So , though there are present 4f^n or 5f^n unpaired electrons, but they hardly make f- block elements/ compounds ferromagnetic.

[F] Lastly, coming to the d- block elements/ their compounds. The outermost electron enters 3d of 4d or 5d[ penultimate{ outermost but one} shell] which being more exposed energically interact strongly. Thus eneries are affected on formation of their compounds or when the elements form bonds on aggregate formation. This means that their aggregates show STRONGLY AN IN PHASE ADDITIVE PROPERTY; meaning therby that they CAN SHOW PARAMAGNETISM AS WELL AS FERROMAGNETISM .

So the conclusion is that- It is only the presence of unpaired electrons in “d” orbitals which make the transition metals/ their compounds ferromagnetic.

{G} Ferroelectricity is a property of certain materials that have a spontaneous electric polarization which can be reversed by the application of an external electric field.Croconic acid is an excellent organic ferroelectric and its spontaneous polarization is close to that of barium titanate; one of the representative ferroelectric ceramics.

Again, there may be a misconception that the ferroelectric mateials need to be paramagnetic/ ferromagnetic. On the contrary, there need not be present any any unpaired electrons. More so, there should not be any electron in “d” subshell.

It is reasoned out as follows:

(i)Typically, materials demonstrate ferroelectricity only below a certain phase transition temperature, called the Curie temperature, Tc, and are paraelectric above this temperature.

(ii) The results show that the electronic polarization is 20 times the ionic polarization.

(iii)The two(electronic polarization and ionic polarization ) point in opposite directions.

So:

(a) it will be better if they do not have unpaired electrons at all because the electronic and ionic polarization oppose each other to decrease the net polarizability and the ferroelectricity may desrease or may even vanish.

(b)**If at all the unpaired electrons are a must,they should not be present in “d” subshell because their polarization effect is more than “s” or “f”’ electrons.

*A number of actinide compounds are ferromagnets at room temperature or become ferromagnets below Curie temperature (TC). PuP is one actinide pnictide that is a paramagnet.

d orbital electrons are magnetically active, mainly 3d orbital electrons. In case of 4d and 5d transition metals, the presence of diffuse shell (f orbital) electrons in these created less activation energy to magnetic field and hence results less magnetic ordering. 

@ Manohar Sehgal

Thank you sir for your detailed explanation

The d-orbital electrons are the determinants of the magnetic properties of a material, especially materials that have partially filled d- orbitals. In the case of non magnetic oxides like MgO and ZnO materials, they contain either completely filled d-orbital or unfilled d orbital, so the kind of magnetism they possess in regard of this behaviour is called d - ferromagntism, which is peculiar to non magnetic oxide. Interestingly , research has confirmed that the d ferrogmanetism in MgO is induced by the Mg vacancies.

I am undergoing a research on the applications of d ferromagnetism of transparent oxides

Hi,

The physical properties like magnetization and polarization both are dependent on the degree of overlap with the ligand. Here I am talking about the compounds having coordinated TM here such as octahedral etc. In the energy space the outermost orbitals, say 3dn governs the magnetization as per number of unpaired electrons in the localized picture and it's overlap with the ligand in real space can explain the exchange interaction and hence the molecular field for FM and AFM.

While in the case of ferroelectricity, you TM must be free to move, at least in case of displacive type of polarization. Suppose we have 3d3 system the electrons will resides in the dxy, dyz, and dzx orbitals. The electrons in these orbitals will feel the repulsion from the ligand at the instance of overlap. Same will happen with other occupancy of 3d i.e. particular orbitals filling will limit the degree of overlap in the particular directions via repulsion and less covalency in that direction. But in case of 3d0 your Ti as in case of BaTiO3 is free to go any direction in octahedra and prone to ferroelectricity.

Please comment and correct me, if I am wrong.

Thank you.