Eur. Phys. J. Plus (2021) 136: 1137
https://doi.org/10.1140/epjp/s13360-021-02085-5

Regular Article

Investigation of room-temperature ferromagnetism in perovskite structure via substitutional doping

¹ Department of Physics, Riphah International University, 54000, Lahore, Pakistan
² Department of Physics, International Islamic University, 44000, Islamabad, Pakistan
³ Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha, Saudi Arabia
⁴ Physics Department, Faculty of Science, Port Said University, Port Said, Egypt
⁵ Department of Physics, Quaid-i-Azam University, 45320, Islamabad, Pakistan

^a altaf.urrahman@riphah.edu.pk

Received: 10 August 2021
Accepted: 18 October 2021
Published online: 13 November 2021

Abstract

The C and N atomic doping and co-doping at all possible lattice sites in (STO) perovskite crystal structure have been investigated using density functional theory (DFT) calculations. Calculated formation energies indicate that C and N doping at O site in STO is more stable than at Sr site and Ti site. C incorporation at anion site significantly affects the electronic bandgap of STO by inducing spin-polarized defect states in bandgap region. Consequently transforming the non-magnetic STO to a magnetic with a magnetic moment of 2.0 per C atom and reduced the direct (indirect) bandgap 0.86 eV (0.18 eV) for spin-up (spin-down) channel, respectively. Further, with an increase of C atom concentration the magnetic moment of 2.0 per C atom remains constant, and also, half-metallicity is observed due to spin-down channel. Similarly, N atom substitution at anion site in STO crystal structure induces magnetism of 1.0 . N causes defect states due to which the bandgap of the spin-up channel decreased to 1.68 eV and shows half-metallicity due to the spin-down channel. We found that further increasing the N atom concentration enhanced the half-metallicity by increasing the number of states of the spin-down channel at Fermi energy. Finally, we studied the FM and AFM alignment of the magnetic moments at the dopants C, N and their co-doping in STO with different distances. We found that the C atom prefers AFM states, while the N atom prefers FM states. The calculated Curie temperature for two N atoms at near and far dopants is 722.16 K and 860.91 K, respectively. The results of tailored electronic and magnetic properties above room temperature are interesting from a theoretical perspective and may open opportunities for STO in electronic and spintronic devices.