  The giant magnetoelectric coupling is a very rare phenomenon which has gained
a lot of attention for the past few decades because of fundamental interest as
well as practical applications. Here, we have successfully achieved the giant
magnetoelectric coupling in PbTi1-xVxO3 (x= 0-1) with the help of a series of
generalized-gradient-corrected (GGA), GGA including on-site coulomb repulsion
(U) corrected spin polarized calculations based on accurate density functional
theory. Our total energy calculations show that PbTi1-xVxO3 stabilizes in
C-type antiferromagnetic ground state for x>0.123. With the substitution of V
into PbTiO3, the tetragonal distortion is highly enhanced accompanied by a
linear increase in polarization. In addition, our band structure analysis shows
that for lower x values, the tendency to form 2Dmagnetism of PbTi1-xVxO3
decreases. A non-magnetic metallic ground state is observed for the
paraelectric phase for V concentration (x) = 1 competing with a volume change
of 10% showing a large magnetovolume effect. Our orbital projected DOS as well
as orbital ordering analysis suggest that the orbital ordering plays a major
role in the magnetic to non-magnetic transition when going from ferroelectric
to paraelectric phase. The calculated magnetic anisotropic energy shows that
the direction [110] is the easy axis of magnetization for x= 1 composition. The
present study adds a new series of compounds to the magnetoelectric family with
rarely existing giant coupling between electric and magnetic order parameters.
These results show that such kind of materials can be used for novel practical
applications where one can change the magnetic properties drastically (magnetic
to non-magnetic as shown here) with external electric fieldand vice-versa.
