Fangting Lin

Large strain response in PZT-PZN-PAN lead-based ceramics

Solid solutions of 0.8Pb(Zr0.52Ti0.48)O3-(0.2-x)Pb(Zn1/3Nb2/3)O3-xPb(Al1/2Nb1/2)O3 (PZT-PZN-PAN, PZT-PZN-xPAN) with x from 0 to 0.1 were fabricated and the dielectric, ferroelectric, piezoelectric properties were investigated in detail. Results show the crystal structure changes from coexists of tetragonal and rhombohedral to single rhombohedral phase. At a critical composition of 0.02, a maximum quasi-static piezoelectric coefficient d33 (410 pC/N) was obtained. Furthermore, it is found that the increment of PAN content could lead to increase the strain of PZT-PZN-xPAN ceramics, and a large strain response of ~0.24% with normalized strain Smax/Emax as high as 767 pm/V was obtained for the PZT-PZN-0.1PAN under a low electric field of ~3 kV/mm, which makes it a promising material for solid-state actuator applications.

Highly (222)-oriented pyrochlore PZN-PT thin films prepared by pulsed laser deposition

Highly (222)-oriented 90%Pb(Zn1/3Nb2/3)O3-10%PbTiO3(abbreviated PZN–PT) thin films, about 550nm in thickness, have been successfully grown on (111)Pt/Ti/SiO2/Si substrate by pulsed laser deposition method. Pure pyrochlore phase with highly (222)-preferred orientation, determined by X-ray diffraction, was formed in the PZN–PT thin films when the temperature of substrates is 550°C. FE-SEM investigation shows that the surface appearance and the cross section of the films are smooth and crack-free with some dispersive spherical protrusions. The dielectric constant and loss of the thin films were measured using an impedance analyzer (HP4194A). The dielectric constant ( εr ) and the dissipation factor ( tanδ ) at 1 kHz are 205 and 0.03, respectively.

Structure and magnetic properties of Ge99.04Mn0.96 thin film prepared by thermal evaporation of Mn doped GeO2 ceramic film under hydrogen atmosphere

Ge99.04Mn0.96 thin film was fabricated by thermal evaporation of Mn doped GeO2 ceramic film under hydrogen atmosphere. Secondary phases were not detected by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analyses. The film is p type. Room-temperature ferromagnetism was detected in the film. The ferromagnetic behavior may arise from alignment of the bound magnetic polarons (BMP) mediated by the localized holes in the system as well as ultra small secondary phases unable to be detected by XRD and HRTEM analyses.

Microstructure and electrical properties Of PMNT thin films prepared by a modified sol-gel process

0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMNT) thin films were prepared on (111)Pt/Ti/SiO2/Si substrate by a modified sol-gel process with Nb2O5 as the niobium source. XRD analysis shows that PMNT thin films with pure perovskite were obtained by spin-coating and annealing at 700°C for 20 minutes. The remanent polarization and coercive field of the PMNT thin films are about 7.69μC/cm2 and 80.75kV/cm, respectively. The dielectric and C-V curve of PMNT thin films are also investigated. The dielectric constant ( εr ) reaches 935 and the dissipation factor (tanδ)is about 0.04 at 1kHz.