Multifunctional materials based on rare earth ion doped ferro/piezoelectrics have attracted considerable attention in recent years. In this work, new lead-free multifunctional ceramics of Ca1-x(LiHo)x/2Bi4Ti4O15 were prepared by a conventional solid-state reaction method. The great multi-improvement in ferroelectricity/piezoelectricity, down/up-conversion luminescence and temperature stability of the multifunctional properties is induced by the partial substitution of (Li0.5Ho0.5)(2+) for Ca(2+) ions in CaBi4Ti4O15. All the ceramics possess a bismuth-layer structure, and the crystal structure of the ceramics is changed from a four layered bismuth-layer structure to a three-layered structure with the level of (Li0.5Ho0.5)(2+) increasing. The ceramic with x = 0.1 exhibits simultaneously, high resistivity (R = 4.51 × 10(11)Ω cm), good piezoelectricity (d33 = 10.2 pC N(-1)), high Curie temperature (TC = 814 °C), strong ferroelectricity (Pr = 9.03 μC cm(-2)) and enhanced luminescence. These behaviours are greatly associated with the contribution of (Li0.5Ho0.5)(2+) in the ceramics. Under the excitation of 451 nm light, the ceramic with x = 0.1 exhibits a strong green emission peak centered at 545 nm, corresponding to the transition of the (5)S2→(5)I8 level in Ho(3+) ions, while a strong red up-conversion emission band located at 660 nm is observed under the near-infrared excitation of 980 nm at room temperature, arising from the transition of (5)F5→(5)I8 levels in Ho(3+) ions. Surprisingly, the excellent temperature stability of ferroelectricity/piezoelectricity/luminescence and superior water-resistance behaviors of piezoelectricity/luminescence are also obtained in the ceramic with x = 0.1. Our study suggests that the present ceramics may have potential applications in advanced multifunctional devices at high temperature.

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Multiferroic ceramics of 0.75Bi 1-x Eu x FeO 3 -0.25BaTiO 3 ? 1 mol% MnO 2 were synthesized by a conventional solid state reaction method and the effects of Eu doping on microstructure, ferroelectric, ferromagnetic and piezoelectric properties of the ceramics were investigated. All the ceramics exhibit a pure perovskite structure without any secondary phases. After the addition of Eu 3? ions, the crystal structure of the ceramics is transformed from rhombohedral to tetragonal phase at x = 0.025. The ferroelectricity and ferromagnetism of the ceramics are improved. For the ceramic with x = 0.025, the optimum remanent polarization of 18.3 lC/cm 2 and good piezoelectricity of 82 pC/N are obtained. The saturated magnetization M s and remanent magnetism M r of the ceramics are improved by 165 and 141 % with x increasing from 0 to 0.175, respectively.

The LMNC-BO electrode presents an enhanced cycle performance, better rate capability and structural stability than bare LMNC.