Influence of BiFeO₃ perovskite on the structure and magnetic properties of lead-free Bi_0.5Na_0.4K_0.1TiO₃ films

Abstract

Lead-free (1-x)Bi0.5Na0.4K0.2TiO3-xBiFeO3 (abbreviated as BNKT-xBFO) ferroelectric films with x in the range from 0.00 to 0.10, were synthesized by the chemical solution deposition technique on Pt/Ti/SiO2/Si substrates. The microstructures and magnetic behaviors of BNKT-xBFO films were analyzed in detail as a function of BFO concentration. X-ray diffraction patterns indicated that BNKT-xBFO films were grown with a single-phase perovskite structure. The pure films showed an antiferromagnetic behavior. The magnetic properties of the films were gradually transferred from antiferromagnetic to ferromagnetic properties when BFO concentration was raised. The saturated magnetization (M S) reached the highest value of 10.3 emu cm−3 at the BFO-doped concentration x = 0.10. Our work will contribute to illuminate the impact of BFO (ABO3 perovskite structure) on the magnetic properties of BNKT materials at room temperature.

Influence of heterostructure on structure, electric and magnetic properties of Bi0.5(Na0.80,K0.20)0.5TiO3/BaZrO3 films prepared by the sol–gel method

“…The result is consistent with our previous study which investigated the effect of BiFeO 3 perovskite on the magnetic properties of lead-free BNKT films. 18) Similar behavior was also observed in BNT materials by Hung and co-workers. 25) It is believed that the antiferromagnetic properties in BNKT are contributed by the direct exchange coupling of Ti 4+ -O-Ti 4+ and/or the 3d°empty state of Ti 4+ .…”

“…16) Forming multiferroics based on composite BNKT materials has been proposed as an effective solution to this problem. 17,18) Some configurations of multiferroic composites (such as particles mixed in a matrix, laminated bilayers, homogeneous mixtures, laminated multilayers or fiber multiferroic composites) were reported to possess a magneticelectric behavior numerous orders of amplitude higher than single-phase multiferroics. Moreover these allow flexible selection of the electric and magnetic orders to control properties matching with specific applications.…”

“…Firstly, the introduction of a magnetic phase into a ferroelectric/piezoelectric one can lead to a decrease in mechanical-electric properties and an increase in the complexity of preparation processes. [18][19][20] Secondly, J possesses a relatively high value. Furthermore, there is currently no clear understanding of the mechanism behind the multiferroic properties of BNKT.…”

Effect of Structural Deficiencies on Bi-Ferroic Behaviors of Lead-Free Bi0.5 Na0.40K0.10TiO3 Films

“…Additionally, previous studies indicated that Ti 4+ and Ti 3+ cations coexist within the crystal lattice BNKT [35][36][37][38]. It's supposed that the direct exchange coupling Ti 3+ -O-Ti 3+ contributes to the antiferromagnetic order [39]. However, M s value was significantly enhanced when annealing temperature was risen.…”