Effect of Structural Deficiencies on Bi-Ferroic Behaviors of Lead-Free Bi_0.5 Na_0.40K_0.10TiO₃ Films

Abstract

Lead-free Bi0.5Na0.4K0.1TiO3 (BNKT) ferroelectric films on Pt/TI/SIO2/Si substrates were prepared via a sol-gel spin coating routine. The microstructures and multiferroic behaviors of the films were examined intimately as a function of the annealing time. A rise of annealing time enhanced the crystallization of the films via the perovskite structure. The multiferroic behavior, including simultaneously the magnetic and ferroelectric orders, was observed altogether the films. When the annealing time rose, ferroelectric and magnetic properties were found significantly increased. The remnant polarization (Pr), also as maximum polarization (Pm) respectively increased to the very best values of 11.5 µC/cm2 and 40.0 µC/cm2 under an applied electric field of 500 kV/cm. The saturated magnetization (Ms) of films increased to 2.3 emu/cm3 for the annealing time of 60 minutes. Oxygen vacancies, originating from the evaporation of metal ions during annealing at high temperatures are attributed to the explanation for ferromagnetism within the BNKT films.