LaNiO3 (LNO) thin films were prepared on Pt(111) / Ti / SiO2 / Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared o...LaNiO3 (LNO) thin films were prepared on Pt(111) / Ti / SiO2 / Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared on LNO / Pt / Ti / SiO2 /Si substrates by Sol-gel method. The composition depth profile of a typical up-graded film was determined by using a combination of Auger Electron Spectroscopy (ASE) and Ar Ion Etching. The results confirm that the processing method produces graded composition changes. XRD analysis showed that the graded thin films possessed composite structure of tetragonal and rhombohedral. The dielectric constants of Up-graded and Down-graded thin films were higher than that of each thin film unit. The dielectric constants were 277 and 269 at 10 kHz, respectively. The loss tangents were 0.019 and 0.018 at 10 kHz, respectively. The Hysteresis loops showed that the remanent polarizations of graded thin films were higher than that of each thin film unit, but the coercive fields were smaller. The remanent polarizations of Up-graded and Down-graded thin films were 30.06 and 26.96 μC·cm-2, respectively. The coercive fields were 54.14, 54.23 kV·cm-1, respectively. The pyroelectric coefficients of Up-graded and Down-graded thin films were 4.62, 2.51×10-8 C·cm-2·K-1 at room temperature, respectively. They were higher than that of each thin film unit.展开更多
The PZT thin films were prepared on （111）- Pt/Ti/SiO2/Si substrates by sol-gel method, and lead acetate [Pb（CH3COO）2], zirconium nitrate [Zr（NO3）4] were used as raw materials. The X-ray diffractometer （XRD） an...The PZT thin films were prepared on （111）- Pt/Ti/SiO2/Si substrates by sol-gel method, and lead acetate [Pb（CH3COO）2], zirconium nitrate [Zr（NO3）4] were used as raw materials. The X-ray diffractometer （XRD） and scanning electron microscopy （SEM） were used to characterize the phase structure and surface morphology of the films annealed at 650 ~C but with different holding time. Ferroelectric and dielectric properties of the films were measured by the ferroelectric tester and the precision impedance analyzer, respectively. The PZT thin films were constructed with epoxy resin as a composite structure, and the damping properties of the composite were tested by dynamic mechanical analyzer （DMA）. The results show that the films annealed for 90 minutes present a dense and compact crystal arrangement on the surface; moreover, the films also achieve their best electric quality. At the same time, the largest damping loss factor of the composite constructed with the 90 mins-annealed film shows peak value of 0.9, hi^her than the pure epoxy resin.展开更多
One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks for electromagnetic devices and nanosystems.In this work,the composite Ni0.5Zn0.5Fe2O4（NZFO）/ Pb（Zr0.52Ti0.48）O3（PZT...One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks for electromagnetic devices and nanosystems.In this work,the composite Ni0.5Zn0.5Fe2O4（NZFO）/ Pb（Zr0.52Ti0.48）O3（PZT） nanofibers with average diameters about 65 nm are prepared by electrospinning from poly（vinyl pyrrolidone） （PVP） and metal salts.The precursor composite NZFO/PZT/PVP nanofibers and the subsequent calcined NZFO/PZT nanofibers are investigated by Fourier transform infrared spectroscopy （FT- IR） ,X-ray diffraction （XRD）,scanning electron microscopy （SEM）.The magnetic properties for nanofibers are measured by vibrating sample magnetometer（VSM）.The NZFO/PZT nanofibers obtained at calcination temperature of 900 °C for 2 h consist of the ferromagnetic spinel NZFO and ferroelectric perovskite PZT phases,which are constructed from about 37 nm NZFO and 17 nm PZT grains.The saturation magnetization of these NZFO/PZT nanofibers increases with increasing calcination temperature and contents of NZFO in the composite.展开更多
文摘LaNiO3 (LNO) thin films were prepared on Pt(111) / Ti / SiO2 / Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared on LNO / Pt / Ti / SiO2 /Si substrates by Sol-gel method. The composition depth profile of a typical up-graded film was determined by using a combination of Auger Electron Spectroscopy (ASE) and Ar Ion Etching. The results confirm that the processing method produces graded composition changes. XRD analysis showed that the graded thin films possessed composite structure of tetragonal and rhombohedral. The dielectric constants of Up-graded and Down-graded thin films were higher than that of each thin film unit. The dielectric constants were 277 and 269 at 10 kHz, respectively. The loss tangents were 0.019 and 0.018 at 10 kHz, respectively. The Hysteresis loops showed that the remanent polarizations of graded thin films were higher than that of each thin film unit, but the coercive fields were smaller. The remanent polarizations of Up-graded and Down-graded thin films were 30.06 and 26.96 μC·cm-2, respectively. The coercive fields were 54.14, 54.23 kV·cm-1, respectively. The pyroelectric coefficients of Up-graded and Down-graded thin films were 4.62, 2.51×10-8 C·cm-2·K-1 at room temperature, respectively. They were higher than that of each thin film unit.
基金Supported by the National Natural Science Foundation of China (No. 50772083)China-Japan Cooperation Program(No. 2010DFA51270)the Fundamental Research Funds for the Central Universities
文摘The PZT thin films were prepared on （111）- Pt/Ti/SiO2/Si substrates by sol-gel method, and lead acetate [Pb（CH3COO）2], zirconium nitrate [Zr（NO3）4] were used as raw materials. The X-ray diffractometer （XRD） and scanning electron microscopy （SEM） were used to characterize the phase structure and surface morphology of the films annealed at 650 ~C but with different holding time. Ferroelectric and dielectric properties of the films were measured by the ferroelectric tester and the precision impedance analyzer, respectively. The PZT thin films were constructed with epoxy resin as a composite structure, and the damping properties of the composite were tested by dynamic mechanical analyzer （DMA）. The results show that the films annealed for 90 minutes present a dense and compact crystal arrangement on the surface; moreover, the films also achieve their best electric quality. At the same time, the largest damping loss factor of the composite constructed with the 90 mins-annealed film shows peak value of 0.9, hi^her than the pure epoxy resin.
基金Funded by the National Natural Science Foundation of China (No. 50674048)Research Fund for the Doctoral Program of Higher Education of China(No.20103227110006)
文摘One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks for electromagnetic devices and nanosystems.In this work,the composite Ni0.5Zn0.5Fe2O4（NZFO）/ Pb（Zr0.52Ti0.48）O3（PZT） nanofibers with average diameters about 65 nm are prepared by electrospinning from poly（vinyl pyrrolidone） （PVP） and metal salts.The precursor composite NZFO/PZT/PVP nanofibers and the subsequent calcined NZFO/PZT nanofibers are investigated by Fourier transform infrared spectroscopy （FT- IR） ,X-ray diffraction （XRD）,scanning electron microscopy （SEM）.The magnetic properties for nanofibers are measured by vibrating sample magnetometer（VSM）.The NZFO/PZT nanofibers obtained at calcination temperature of 900 °C for 2 h consist of the ferromagnetic spinel NZFO and ferroelectric perovskite PZT phases,which are constructed from about 37 nm NZFO and 17 nm PZT grains.The saturation magnetization of these NZFO/PZT nanofibers increases with increasing calcination temperature and contents of NZFO in the composite.
