Large difference between the magnetic properties of Ba and Ti co-doped BiFeO$_3$ bulk materials and their corresponding nanoparticles prepared by ultrasonication

TL;DR

This study compares the magnetic properties of Ba and Ti co-doped BiFeO3 bulk materials and their nanoparticles, revealing significant differences likely due to impurity phases and preparation methods, with implications for magnetic and electrical performance.

Contribution

It demonstrates that ultrasonication can effectively remove impurity phases from BiFeO3 materials, significantly altering their magnetic properties compared to bulk samples.

Findings

Impurity phases are eliminated in nanoparticles via ultrasonication.

Magnetic properties differ markedly between bulk and nanoparticle forms.

Leakage current density is reduced in ultrasonically prepared nanoparticles.

Abstract

The ceramic pellets of the nominal compositions Bi$_{0.7}$Ba$_{0.3}$Fe$_{1-x}$Ti$_x$O$_3$ (x = 0.00-0.20) were prepared initially by standard solid state reaction technique. The pellets were then ground into micrometer-sized powders and mixed with isopropanol in an ultrasonic bath to prepare nanoparticles. The X-ray diffraction patterns demonstrate the presence of a significant number of impurity phases in bulk powder materials. Interestingly, these secondary phases were completely removed due to the sonication of these bulk powder materials for 60 minutes. The field and temperature dependent magnetization measurements exhibited significant difference between the magnetic properties of the bulk materials and their corresponding nanoparticles. We anticipate that the large difference in the magnetic behavior may be associated with the presence and absence of secondary impurity phases in the bulk materials and their corresponding nanoparticles, respectively. The leakage current density of the bulk materials was also found to suppress in the ultrasonically prepared nanoparticles compared to that of bulk counterparts.