Size dependent magnetic and electrical properties of Ba-doped nanocrystalline BiFeO$_3$

TL;DR

This study investigates how particle size influences the magnetic and electrical properties of Ba-doped BiFeO3 nanoparticles, revealing size-dependent enhancements and complex interactions affecting multiferroic behavior.

Contribution

It provides new insights into size-dependent multiferroic properties of Ba-doped BiFeO3 nanoparticles, highlighting the effects of particle size, doping, and defect interactions.

Findings

Magnetic and electrical properties improve with Ba doping and smaller particle size.

A size-dependent transition from metamagnetic to non-metamagnetic behavior.

Suppression of spiral spin cycloid with decreasing particle size.

Abstract

Improvement in magnetic and electrical properties of multiferroic BiFeO$_3$ in conjunction with their dependence on particle size is crucial due to its potential applications in multifunctional miniaturized devices. In this investigation, we report a study on particle size dependent structural, magnetic and electrical properties of sol-gel derived Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles of different sizes ranging from $\sim$ 12 to 49 nm. The substitution of Bi by Ba significantly suppresses oxygen vacancies, reduces leakage current density and Fe$^{2+}$ state. An improvement in both magnetic and electrical properties is observed for 10 % Ba-doped BiFeO$_3$ nanoparticles compared to its undoped counterpart. The saturation magnetization of Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles increase with reducing particle size in contrast with a decreasing trend of ferroelectric polarization. Moreover, a first order metamagnetic transition is noticed for $\sim$ 49 nm Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles which disappeared with decreasing particle size. The observed strong size dependent multiferroic properties are attributed to the complex interaction between vacancy induced crystallographic defects, multiple valence states of Fe, uncompensated surface spins, crystallographic distortion and suppression of spiral spin cycloid of BiFeO$_3$.