Synthesis and characterization of Bi1-xDyxFeO3 nanoparticles using ultrasonication technique

Abstract

The structural, morphological, magnetic, ferroelectric and optical properties of Dysprosium (Dy) doped BiFeO3 multiferroic materials are reported. The bulk polycrystalline Bi0.9Dy0.1FeO3 samples were synthesized using solid state reaction technique and their nano counterparts were prepared using ultrasonic probe sonication. XRD patterns demonstrated significant improvement of phase purity due to Dy substitution both in bulk sample and corresponding nanoparticles. The FESEM images were carried out to analyze the surface morphology of bulk sample as well as to determine the size and distribution of the synthesized nanoparticles. From this, the particle size was found to vary from 75 to150 nm, 75 to 100 nm, and 50 to 100 nm, for 30, 60 and 90 minutes sonication, respectively. The magnetization of Dy doped bulk BiFeO3 was enhanced significantly compared to that of undoped BiFeO3. On the contrary, compared to Dy doped bulk BiFeO3 the magnetization of their corresponding nanoparticles prepared by ultrasonication was found to decrease. Furthermore, leakage current density measurements were performed where, interestingly, comparable performance was found for Bi0.9Dy0.1FeO3 bulk and its corresponding nanoparticles. Moreover, the polarization versus electric field measurements showed higher remanent polarization and coercive field for nanoparticles compared to their bulk samples, which might be associated with leaky behavior generated from oxygen related defects of the nanoparticles. Overall, this investigation provides evidence of Bi0.9Dy0.1FeO3 multiferroic having enhanced structural purity, magnetic and ferroelectric properties over undoped BiFeO3. In particular, it opens up the pathway of a material with equivalent bulk and nano leakage current performance, which may be useful in many applications.