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Effect of additional Zn2+ dopant on the ferromagnetism (FM) of Co doped CeO2 nanoparticles was studied. The Zn and Co co-doped CeO2 nanoparticles (Ce0.97−xZnxCo0.03O2: where x = 0, 0.01, 0.03, 0.05) were prepared by sol-gel technique. The crystal structure, morphology, and magnetic properties were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (Raman) and physical property measurement system (PPMS). XRD and Raman studied showed that certain amount of Zn2+ can readily be incorporated into the lattice of Co doped CeO2 with single-phase of CeO2 original cubic fluorite crystal structure, and no ferromagnetic secondary phase was observed. SEM images show Zn and Co co-doped CeO2 nanoparticles were spherical and uniform size. The PPMS studied indicate that the room-temperature FM of Co doped CeO2 nanoparticles increase with additional Zn2+ dopant. This result is helpful in understanding the origin of FM in diluted magnetic oxides (DMO) as well as improving the magnetic property of DMO. [ABSTRACT FROM AUTHOR]

BiCeFe(MgTi)O ( x = 0, 0.05, 0.10, 0.20, 0.25) thin films were synthesized by a sol-gel method. The structural, electrical and magnetic properties of BiCeFe(MgTi)O ( x = 0, 0.05, 0.10, 0.20, 0.25) thin films have been investigated. BiFeO thin film possessed a perovskite-type rhombohedral structure with space group R3c, and the average grain size decreased as the concentration of Ce, Mg and Ti co-doping increased. The leakage current densities of BiFeO co-doping with Ce, Mg and Ti ions exhibited a significant reduction compared with that of BiFeO thin film. Compared with the leakage current density of BiFeO thin film (4.19 × 10 A/cm), the leakage current density of BiCeFeMgTiO thin film was reduced by about four orders of magnitude (1.05 × 10 A/cm) under the electric field of 300 kV/cm. Well-defined ferroelectric loops were obtained and the polarization increased with the increase of Ce, Ti and Mg co-doping. The remanent polarization of BiCeFeMgTiO thin film (2 P ~34.9 μC/cm) was approximately four times larger than that of pure BiFeO (2 P ~7.8 μC/cm) under the applied field of 300 kV/cm. The magnetization under 10 kOe magnetic field of BiCeFe(MgTi)O thin films increased with the increasing concentration of Ce, Mg and Ti co-doping. The improvement of magnetic behaviors for BiFeO co-doping with Ce, Mg and Ti ions thin films were observed significantly, cooperating with the enhanced ferroelectricity which indicated that BiFeO co-doping with Ce, Mg and Ti ions thin films will be the promising materials in the application to magnetoelectric devices. [ABSTRACT FROM AUTHOR]

(1- x)BiFeO- xCaTiO ((1- x)BFO- xCTO, x = 0, 0.05, 0.10, 0.15, 0.20) thin films were successfully grown on Pt(111)/Ti/SiO/Si(100) substrates using a sol-gel spin coating method. The structure stabilities of BFO thin films were improved by introducing CTO due to the increase of their tolerance factor. The X-ray diffraction patterns indicated that all the samples had a single perovskite structure. The merging phenomenon of (110) and (104) diffraction peaks demonstrated a distortion of the lattice structure in BFO thin films by introducing CTO. The atomic force microscope showed all the samples had dense, crack-free and uniform morphology. The leakage current density decreased with the increasing of CTO contents. At the applied electric field of 300 kV/cm, the leakage current density of the 0.85BFO-0.15CTO was 1.42 × 10 A/cm, which is about 4 orders of magnitude lower than that of the pure BFO thin film (5.78 × 10 A/cm). The leakage conduction mechanism showed Ohmic conduction for all thin films in the low electric field region. In the high electric field region, the leakage mechanisms were dominated by the space-charge-limited current behavior for 0.80BFO-0.20CTO and the Fowler-Norheim tunneling for (1- x)BFO- xCTO ( x = 0.10, 0.15) thin films. The remnant polarization (2 P ) and spontaneous polarization ( P ) of (1- x)BFO- xCTO ( x = 0.10, 0.15, 0.20) were obviously improved. The 0.85BFO-0.15CTO thin film showed the best ferroelectricity with large remnant polarization of 39.88 μC/cm while the remnant polarization of the pure BFO was 3.74 μC/cm at the electric field of 300 kV/cm. The absorption edges of (1- x)BFO- xCTO thin films are blue-shift with the increasing of x value. The structural, optical properties and ferroelectricity of BFO thin films were improved by introducing CTO. [ABSTRACT FROM AUTHOR]

Well-crystallized bismuth ferrite (BiFeO) and Mn-doped BiFeO particles (BiFeMnO: x = 0, 0.02, 0.06, 0.10, 0.15, 0.20) were successfully prepared using a hydrothermal method with the mineralizer of KOH. The phase structure, morphology, optical and magnetic properties of the as-prepared samples were investigated by X-ray diffraction (XRD), scanning electron microscope, Raman spectroscopy, and physical properties measurements system, respectively. Phase purity of all samples was confirmed from XRD measurements. Spherical aggregated structure of all samples was observed at low magnification and the spherical particles consist of large amounts of small particles. The size of these small particles decrease with the increasing Mn content. It was found that with the increasing of Mn content, within the range of x = 0.06-0.20, a structural phase transition from rhombohedral to orthorhombic system occurs. Maximum magnetization at 20 K Oe was obtained in BiFeMnO and weak ferromagnetic properties were observed as the Mn concentration exceeds 0.1. [ABSTRACT FROM AUTHOR]

(BaCa)(ZrTi)TaO ceramics (BCZTT, 0 ≤ x ≤ 3.0 mol%) were prepared via a conventional solid-state reaction method, and the effect of Ta substitution on the microstructure and electrical properties of the BCZTT ceramics was investigated. A pure perovskite structure was obtained in all of these samples. The microstructure of the BCZT ceramics is strongly affected by Ta doping. Low-concentration Ta addition ( x = 0.1 mol%) promotes the grain growth of the BCZT ceramics. However, high-concentration Ta addition ( x > 0.5 mol%) effectively hinders the grain growth. The dielectric, ferroelectric and piezoelectric properties of the BCZT ceramics are improved by addition of a small amount of Ta. For the ceramics with x = 0.3 mol%, electrical performance reaches optimum: ε = 7,770, T (the temperature of the dielectric maximum) = 101.8 °C, P = 17.9 μC/cm, P = 9.1 μC/cm, E = 0.54 kV/mm and d = 303 pC/N. The T of the BCZTT decreases with the increasing Ta concentration. The relaxor properties of undoped and Ta-doped BCZT ceramics were depicted, and the diffusivity increases with the increasing Ta contents. [ABSTRACT FROM AUTHOR]