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.
