| Bi3.15La0.85Ti3O12 (BLT) thin films grown on LaNiO3 (LNO) buffered Si(100) substrate were prepared by chemical solution deposition. The samples was annealed at 600℃ by rapidly thermal annealing (RTA) in oxygen and nitrogen atmosphere, respectively. X-ray diffraction results showed that, the sample annealed in oxygen atmosphere exhibited pure perovskite and mixed polycrystalline orientation. Field-emission scanning electron microscopy results revealed that the average grain size of the sample is about 50 nm. The remanent polarization (Pr) and coercive electric field (Ec) values for the BLT films annealed in pure oxygen atmosphere and nitrogen atmosphere were 54.32 μC/cm2 and 30.46 kV/cm, 42.74 μC/cm2 and 43.35 kV/cm, respectively. The leakage current density is 8×10-4 A/cm2 in oxygen atmosphere which is about one order of magnitude lower than that of BLT thin films in nitrogen atmosphere under the same field. The saturation magnetization of BLT films on Si substrate with and without LNO buffer-layer were 0.112 emu/cm3 and 0.057 emu/cm3, respectively. Defects, strain stress can induce the magnetic property, LNO electrode can enhance the magnetic property of BLT film.Ni0.5Zn0.5Fe2O4 (NZFO) thin films grown on LaNiO3 (LNO) buffered Si (100) substrate were prepared by chemical solution deposition. The samples were annealed at 600℃ by RTA in oxygen and nitrogen atmosphere, respectively. X-ray diffraction results showed that the sample annealed in oxygen atmosphere exhibited mixed polycrystalline orientation, while the sample in nitrogen atmosphere is highly a-axis oriented. Field-emission scanning electron microscopy results revealed that the average grain size of the sample is about 20 nm. The remanent polarization values of the NZFO films annealed in pure oxygen and nitrogen atmosphere were 22.21 μC/cm and 82.34 μC/cm, respectively. The sample orientation, oxygen vacancy and tensile strain caused by the difference thermal expansion of the NZFO film and LNO buffered Si substrate enhanced the ferroelectric property. The magnetic measurement gives a typical value of the saturation magnetization of 0.767 emu/cm3 annealed in oxygen atmosphere, and the saturation magnetization in nitrogen atmosphere decreased. In the low electric field region (E<300 kV/cm), the dominant mechanism for leackage current is Ohmic and the Schottky Emission mechanisms; In the high electric field region (E>300 kV/cm), the space-charge-limited-current mechanism is dominant.Bi4Ti3O12 (BiT) and Bi2Ti207 (BTO) thin films grown on Si (100) substrate were prepared by chemical solution deposition. The samples were annealed at 600℃ by RTA in oxygen atmosphere. The X-ray diffraction, Surface morphology, ferroelectric properties, ferromagnetism properties, Ⅰ-Ⅴ characteristics and fatigue resistance of the films were investigated. X-ray diffraction results showed that samples annealed in oxygen atmosphere exhibited mixed polycrystalline orientation. Surface morphology results revealed that the roughness average is about 18 nm. The remanent polarization values of the BiT and BTO films annealed in pure oxygen were about 15 μC/cm2 and 10 μC/cm2, respectively. Compared with the BTO thin film, it also found that BiT thin film have lower leakage current, better fatigue resistance. It is the first time to discover the ferromagnetism properties in BiT and BTO films.NiZn ferrite NixZn1-xFe2O4 (NZFO, x=0.2,0.3,0.4 and 0.5) ceramics prepared by co-precipitation technique. The effect of composition on dielectric relaxation has been studied. The X-ray diffraction patterns showed that the sample has a perfect spinel structure and lattice parameter decreases with increase in Ni content. The temperature dependence of permittivity of the ceramics has been investigated over a broad temperature with the frequency range from 1 to 100 kHz. With increasing frequency, the broad permittivity maximum values becoming broader and shifting to higher temperatures, signify a relaxer-type behavior. Two activation energy values about 0.96 and 0.43 eV in different temperature regions were calculated. The Cole-Cole figures showed single semicircles, which are non-ideal Debye model samples. The grain boundaries resistance increases with the concentration of Ni. According to the modified Curie-Weiss law, we got the diffusivity factor of the NZFO ceramics from 1.66 to 2.02 with x increasing from 0.2 to 0.5, respectively.In addition, the PbTiO3(PTO), PbZr0.53Ti0.47O3(PZT) and SrTiO3(STO) thin films were prepared by chemical solution deposition. The Surface morphology, ferroelectric properties and ferromagnetism properties of the films were investigated. It is the first time to discover the ferromagnetism properties in PTO, PZT and STO films. We also find that the annealing atmosphere, substrates and buffer layer can effect the ferromagnetism properties of BLT thin films. |
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