Effects of Ho and Ti Doping on Structural and Electrical Properties of BiFeO₃ Thin Films

Abstract

Effects of Ho and Ti ions individual doping and co‐doping on the structural, electrical, and ferroelectric properties of the BiFeO3 thin films are reported. Pure BiFeO3, (Bi0.9Ho0.1)FeO3, Bi(Fe0.98Ti0.02)O3+δ, and (Bi0.9Ho0.1)(Fe0.98Ti0.02)O3+δ thin films were prepared on Pt(111)/Ti/SiO2/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/cm2 at 100 kV) and improved ferroelectric properties, such as a large remnant polarization (2Pr) of 52 μC/cm2 and a low coercive field (2Ec) of 886 kV/cm, were observed for the (Bi0.9Ho0.1)(Fe0.98Ti0.02)O3+δ thin film. Fast current relaxation and stabilization observed in the (Bi0.9Ho0.1)(Fe0.98Ti0.02)O3+δ imply effective reduction and neutralization of charged free carriers.

Multiferroic bismuth ferrite-based materials for multifunctional applications: Ceramic bulks, thin films and nanostructures

“…In general, ions substitutions for Bi site mainly include La, 29,59,[291][292][293]298,314 Nd, 54,288,292 Gd, 290 Ba, 294 Ce, 309 Eu, 319 Sm, 320,623,855,856 Tb, 329 Sr, 335 and Ho. 341 As shown in Ion substitutions for Fe site have been shown to improve the overall ferroelectric properties of BFO thin films by decreasing defect concentrations. Table 14 shows electrical and magnetic properties of BFO thin films with ion substitutions for Fe site.…”

Improved multiferroic properties in (Ho, Mn) co-doped BiFeO3 thin films prepared by chemical solution deposition

“…[5,6]. However, the practical applications of BFO in electronic devices are limited due to the serious leakage-current problem, which will make it difficult to obtain a large remanent polarization in BFO.…”

Effects of Ba and Ti co-doping on BiFeO3 multiferroic ceramics optimized through two-step doping

“…Co-doping of two or more elements to BiFeO 3 simultaneously thus seems inevitable for most applications of BiFeO 3 . As a matter of fact, a large number of investigations have already been conducted on BiFeO 3 co-doped with various element combinations [14][15][16], including Ba and Ti, and some very promising results have been obtained. In this paper, we will report a surprising finding revealed for the co-doping of Ba and Ti to BiFeO 3 .…”