Effects of <scp> <scp>Ho</scp> </scp> and <scp> <scp>Ti</scp> </scp> Doping on Structural and Electrical Properties of <scp> <scp>BiFeO</scp> </scp> ₃ Thin Films

Abstract

Effects of Ho and Ti ions individual doping and co‐doping on the structural, electrical, and ferroelectric properties of the BiFeO 3 thin films are reported. Pure BiFeO 3 , ( Bi 0.9 Ho 0.1 ) FeO 3 , Bi ( Fe 0.98 Ti 0.02 ) O 3+δ, and ( Bi 0.9 Ho 0.1 )( Fe 0.98 Ti 0.02 ) O 3+δ thin films were prepared on Pt (111)/ Ti / SiO 2 /Si(100) substrates by using a chemical solution deposition method. All thin films were crystallized in distorted rhombohedral structure containing no secondary or impurity phases confirmed by using an X ‐ray diffraction study. Changes in microstructural features, such as grain morphology and grain size distribution, for the doped samples were analyzed by a scanning electron microscopy. From the experimental results, a low electrical leakage (1.2 × 10 −5 A/cm 2 at 100 kV) and improved ferroelectric properties, such as a large remnant polarization (2 P r ) of 52 μC/cm 2 and a low coercive field (2 E c ) of 886 kV/cm, were observed for the ( Bi 0.9 Ho 0.1 )( Fe 0.98 Ti 0.02 ) O 3+δ thin film. Fast current relaxation and stabilization observed in the ( Bi 0.9 Ho 0.1 )( Fe 0.98 Ti 0.02 ) O 3+δ imply effective reduction and neutralization of charged free carriers.