# Giant magnetoelectric coupling in multiferroic PbTi$_{1-x}$V$_x$O$_{3}$ from density functional calculations

## TL;DR

This study demonstrates giant magnetoelectric coupling in PbTi$_{1-x}$V$_x$O$_{3}$ through density functional calculations, revealing magnetic phase transitions, enhanced polarization, and potential for electric control of magnetic properties.

## Contribution

The paper reports the first theoretical prediction of giant magnetoelectric coupling in PbTi$_{1-x}$V$_x$O$_{3}$, including detailed analysis of magnetic states, polarization, and orbital effects.

## Key findings

- PbTi$_{1-x}$V$_x$O$_{3}$ stabilizes in C-type antiferromagnetic state for x>0.123
- Polarization increases linearly with V substitution
- A large magnetovolume effect and magnetic to non-magnetic transition observed

## Abstract

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.