Occurrence of spintronics behaviour (half-metallicity, spin gapless semiconductor and bipolar magnetic semiconductor) depending on the location of oxygen vacancies in BiFe0.83Ni0.17O3.

P Iyyappa Rajan,S Mahalakshmi,Sharat Chandra

doi:10.1098/rsos.170273

Abstract

The current communication signifies the effect of oxygen vacancies (OVs) both qualitatively and quantitatively in multiferroic BiFe0.83Ni0.17O3 by an in-depth atomic-level investigation of its electronic structure and magnetization properties, and these materials have a variety of applications in spintronics, optoelectronics, sensors and solar energy devices. Depending on the precise location of OVs, all the three types of spintronic material namely half-metallic, spin gapless semiconductor and bipolar magnetic conductor have been established in a single material for the first time and both super-exchange and double-exchange interactions are possible in accordance with the precise location of OVs. We have also calculated the vacancy formation energies to predict their thermodynamic stabilities. These results can highlight the impact and importance of OVs that can alter the multiferroic properties of materials.

Highlights

Multiferroic materials have been perceived as an ideal candidate for novel applications that include but are not limited to spintronics, magnetic field sensors and multiple state memory elements [1]
We have found that the magnetization values of Fe and Ni ions are influenced by the presence and precise location of oxygen vacancies (OVs)
When 1 OV is nearer to Ni (A), the net magnetic moment is slightly enhanced to 27.315 μB and when 1 OV is farther to Ni (D) there is no significant change in the magnetic moment

Summary

Introduction

Multiferroic materials have been perceived as an ideal candidate for novel applications that include but are not limited to spintronics, magnetic field sensors and multiple state memory elements [1]. Ferroelectric polarization measurements of BFO samples show high electrical leakage currents thereby limiting its applications in memory storage devices [2]. It has been well established that by means of site-engineering approach (doping at Bi and Fe sites) the leakage current can be significantly controlled [3,4] and in particular, doping of aliovalent ions at Fe site greatly influences the electronic structure, releases net magnetization by destroying the cycloid-type magnetic structure and enhances the optical properties of BFO [5]. OVs do occur in the synthesis of BFO samples and both qualitative and quantitative presence of OVs play a vital role in modulating the electronic, magnetic and optical properties of Ni-doped BFO. By employing first principles DFT calculations, we have made an effort in exploring the behaviour of BiFe0.83Ni0.17O3 by varying the OVs concentration both qualitatively and quantitatively. The details of the calculations performed are mentioned below in the computational methodology section

Methods

Results

Conclusion