Effect of A and B-site substitution with Pb, La and Ti on phase stabilization and multiferroic properties of BiFeO3

Authors

G. Hassnain Jaffari, Quaid-i-Azam University, Pakistan
Abdus Samad, Quaid-i-Azam University, Pakistan
Asad M. Iqbal, Quaid-i-Azam University, Pakistan
Shahzad Hussain, Quaid-i-Azam University, Pakistan
Arif Mumtaz, Quaid-i-Azam University, Pakistan
Mohammad Sohail Awan, Agha Khan UniversityFollow
M. Siddique, PINSTECH, P.O. Nilore, Pakistan
S. Ismat Shah, Astronomy, University of Delaware, USA

Document Type

Article

Department

Surgery

Abstract

Abstract

The work presents a comparative study of the effects of divalent (Pb), trivalent (La) and tetravalent (Ti) substituents on the multiferroic properties of BiFeO₃ (BFO). Both A and B-sites were substituted to obtain the compositions i.e. (Bi_1−x−yLa_xPb_y)(Fe_1−zTi_z)O₃ (x, y = 0, 0.1, 0.2 and z = 0, 0.05, 0.1, 0.15). Each of the substituent was particularly chosen i.e. Pb was chosen to keep the lone pair character which is the similar case as Bi ion. Additionally isovalent La was chosen to achieve single phase by reducing Bi volatization. Both these ions, on substitution, stabilized the crystal structure and suppressed the formation of extra phases which are unavoidable in pure BFO. All the Ti substituted and Bi_0.8La_0.2FeO₃ compositions exhibited rhombohedral perovskite (R3c) phase, while Bi_0.8Pb_0.2FeO₃ and Bi_0.8La_0.1Pb_0.1FeO₃ exhibited cubic phase. Mössbauer measurements revealed that impurity phase in case of compositions with divalent and trivalent substituents, disappeared completely when Ti substituted Fe. For all the compositions Fe ions were found in +3 state. High temperature dielectric properties showed that all the compositions were ferroelectric with paraelectric transition lying well above the room temperature. Weak ferromagnetism was found in Ti substituted compositions where coercivity was found to increase as the Ti concentration increases. All the BFO samples substituted with Pb, exhibited a dielectric anomaly in the temperature range, 100 °C ⩽ T ⩽ 250 °C. A systematic reduction in the intensity of the dielectric anomaly peak was observed as a function of Ti concentration which indicates that the anomaly is related to the conductivity and is element specific. However, Mössbauer data revealed absence of Fe²⁺ state, which ensured that it was not related with the presence of Fe²⁺ ions. Saturation polarization was found to increase as Ti concentration increased from 0% to 10%.

Publication (Name of Journal)

Journal of Alloys and Compounds

Recommended Citation

Jaffari, G., Samad, A., Iqbal, A., Hussain, S., Mumtaz, A., Awan, M., Siddique, M., Shah, S. (2015). Effect of A and B-site substitution with Pb, La and Ti on phase stabilization and multiferroic properties of BiFeO3. Journal of Alloys and Compounds, 644(25 September), 893-899.
Available at: https://ecommons.aku.edu/pakistan_fhs_mc_surg_surg/207