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The single Bi4-xEuxTi3O12 and Ni1-xCuxFe2O4 films were prepared via spin-coating method. The composite films of the Bi3.4Eu0.6Ti3O12/Ni0.7Cu0.3Fe2O4, annealed under N2, air and O2, were also prepared via the same method. Compared with the films of Bi4Ti3O12, the films of the Eu-doped Bi4Ti3O12 (Bi4-xEuxTi3O12) exhibit enhanced ferroelectricity. And when x is equal to 0.6, the films of Bi4-xEuxTi3O12 show optimal ferroelectricity. Compared with the undoped NiFe2O4 film, in the films of Ni1-xCuxFe2O4, the doping of Cu2+ enhances ferromagnetism. And when x is equal to 0.3, the Ni1-xCuxFe2O4 films exhibit optimal ferromagnetism. For the composite films of Bi3.4Eu0.6Ti3O12/Ni0.7Cu0.3Fe2O4, annealing atmosphere has a significant impact on the magnetoelectric properties. In comparison with the composite films annealed under N2 and air, the composite films annealed under O2 exhibit optimum ferroelectricity (saturation polarization being 26.3 μC·cm−2), ferromagnetism (saturation magnetization being 385.6 emu·cm−3) and enhanced magnetoelectric coupling effect (magnetoelectric voltage coefficient being 86.4 mV·(cm·Oe)−1). This is beneficial for the applications in magnetoelectric functional devices.

Lead-free piezoelectric ceramics [(Ba 0.85 Ca 0.15 )(Ti 0.90 Zr 0.10 )O 3- xBiErO 3 (BCTZ-xBE)] doped with a new doping material BiErO 3 (BE) has been synthesized successfully via solid state reaction technique, and their structural, dielectric, ferroelectric, and piezoelectric properties have been investigated. A high dielectric constant with very low dielectric loss and high remnant polarization followed by a low coercive field has been obtained with the addition of x = 0.5 BE. Bulk ferroelectric hysteresis loops were obtained with a maximum polarization P max = 26.7 μC/cm 2 and a saturation polarization P s = 16.65 μC/cm 2 along with a coercive field of E c ≈ 2.45 kV/cm. Results demonstrate an induced-strain increasing from ~ 0.11 to ~ 0.24 for x = 0.5, excellent piezoelectricity with d 33 = 560 pC/N, k p = 56%, Q m = 196, e m = 11,200 and tan δ = 0.01.

0.95 (Na0.5Bi0.5)TiO3–0.05 BaTiO3 + 2 wt% Bi2O3 (NBT–BT3) ceramic was used as a target and NBT–BT3 thin films were deposited at room temperature by changing the RF power from 75 W to 150 W. The thickness of the NBT–BT3 thin films increased from 203 to 478 nm as the RF power increased from 75 W to 150 W. At 75 W RF power, the deposited NBT–BT3 thin films displayed defective surfaces, whereas at RF power ≧ 100 W, the NBT–BT3 thin films displayed smooth surfaces. The grain sizes also increased with increasing RF power. In addition, the remanent polarization and saturation polarization increased with increasing RF power. The coercive field first increased, reached a maximum at 100 W, then decreased with increasing RF power.

Effects of compressive stress on the ferroelectric properties of ceramics in PZT–PZN systems were investigated. (1 − x )Pb(Zr 1/2 Ti 1/2 )O 3 ( x Pb(Zn 1/3 Nb 2/3 )O 3 or (1 − x )PZT–( x )PZN ( x = 0.1–0.5) ceramics were prepared by a conventional mixed-oxide method. The ferroelectric properties under compressive stress of the PZT–PZN ceramics were observed at stress levels up to 170 MPa using a compressometer in conjunction with a modified Sawyer–Tower circuit. It was found that with increasing compressive stress the area of the ferroelectric hysteresis (P–E) loops, the saturation polarization ( P sat ), the remanent polarization ( P r ), and the coercive field ( E c ) decreased. These results were interpreted through the non-180° ferroelectric domain switching processes.