Tb-doped Films Research Articles

Magneto-optical properties of Ce3+ and Tb3+-doped silico-phosphate sol-gel thin films

Ce3+ and Tb3+-doped silico-phosphate films were obtained by using the sol-gel method, followed by the spin-coating deposition on silicon substrate. The homogeneity of the films was investigated by the conoscopy method. It was observed that the analysed films are isotropic but relatively inhomogeneous due to the specificity of the deposition technique. The morphology of the sol-gel films was investigated by Scanning Electron Microscopy and Atomic Force Microscopy. The elemental composition was determined by Energy Dispersive X-ray analysis. The magneto-optical investigations evidenced the capability of Ce and Tb-doped films of less than 2 µm thickness to produce measurable Kerr rotations of 1 mdeg/T and 0.28 mdeg/T, respectively.

Effects of Tb doping on structural and electrical properties of 47(Ba0.7Ca0.3)TiO3–0.53Ba(Zr0.2Ti0.8)O3 thin films at various annealing temperature by pulsed laser deposition

The ceramic thin films of 47(Ba0.7Ca0.3)TiO3–0.53Ba(Zr0.2Ti0.8)O3 (BCZT) + x (x = 0.2, 0.3, 0.4 and 0.5)mol% Tb were grown on Pt(111)/Si substrates with various annealing temperature by pulsed laser deposition. The XRD spectra confirm that Tb element can enhance the (l10) and (111) orientations in ceramic films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images show that Tb-doping can increase particle size effectively. The surface of Tb-doped film annealed at 800℃ is uniform and crack-free, and the average particle size and mean square roughness (RMS) are about 280nm and 4.4nm, respectively. Comparing with pure BCZT, the residual polarization (Pr) of 0.4mol% Tb-doped film annealed at 800℃ increase from 3.6 to 9.8 μC/cm2. Moreover, the leakage current density value of Tb doped films are one order of magnitude (5.33 × 10−9−1.97 × 10−8A/cm2 under 100kV/cm) smaller than those of pure BCZT films (1.02 × 10−7A/cm2).

Photoluminescence properties of Tb3+ and Eu3+ ions hosted in TiO2 matrix

Photoluminescence (PL) properties of TiO2:Eu and TiO2:Tb films growth by sol–gel on glass substrates are reported. For TiO2:Eu films the spectral lines are due to the 5D0→7Fj Eu3+ electronic levels and its intensity increases as the content of Eu in the films. For the TiO2:Tb films not clear spectral lines coming from the Tb3+ electronic structure is detected, just broad bands due to the Tb3+ and TiO2 defects levels were observed. The slight signal observed from Tb3+ electronic levels, for the Tb-doped films, is removed as soon as the samples are annealed at 600°C. The results show that the Eu3+ and Tb3+ are incorporated in different crystallographic sites in the TiO2 amorphous matrix.

Magnetostriction and angular dependence of ferromagnetic resonance linewidth in Tb-doped Ni0.8Fe0.2 thin films

We present the dependence of the magnetostriction in Ni0.8Fe0.2 films on Tb and Gd doping concentration and compare with the measured doping dependence of the high-frequency damping. While the magnetostriction and the high-frequency damping are correlated, the dependence is complicated. In particular, the high-frequency damping parameter α increases rapidly (α=0.008–0.84) with a modest increase in the magnetostriction (λs=−0.6×10−6 to 5.7×10−6) for Tb doping concentrations up to 10%. For Gd doping, the high-frequency damping changes slowly (α=0.008–0.02) as the doping concentration is increased to 10%, whereas the increase in magnetostriction is similar to that observed in the Tb-doped films. Further, it is possible to achieve low magnetostriction (λs=2×10−6) near the region of critical damping. Measurements of the angular dependence of the ferromagnetic resonance linewidth in Tb-doped Ni0.8Fe0.2 films show little change similar to the behavior observed in undoped Ni0.8Fe0.2 films, although the linewidths are considerably larger. This is in contrast to systems such as Ni0.8Fe0.2 on NiO, which have a large angular dependence indicating that the relaxation process proceeds through the generation of spin waves. The enhanced damping in the Tb-doped films appears, therefore, to be mediated through direct phonon generation.

Blue, green and red cathodoluminescence of Y 2O 3 phosphor films prepared by spray pyrolysis

Thin films of yttrium oxide doped separately with Eu 3+, Tb 3+ and Tm 3+ were deposited by spray pyrolysis. The effect of preparation conditions on the structural and cathodoluminescent (CL) properties of the thin films was investigated. Films containing Eu 3+, Tb 3+ and Tm 3+ emitted red, green and blue colors, respectively. Films of yttrium oxide doped with Tm were evaluated in detail. The blue emission of these films had CIE chromaticity coordinates of x=0.158 and y=0.150 with a dominant wavelength of 476 nm and a color purity of 78% compared to CIE Standard Source C. The CL intensity of the films under 5 kV beam excitation and a current density of 5 mA/cm 2 depended strongly on annealing conditions and thulium doping concentration. For Tm-doped films the maximum luminance was 30.4 cd/m 2 and there was a linear relationship between the CL intensity and excitation voltage. A luminance of 255 cd/m 2 was obtained for the Eu-doped film. The dominant wavelength was 604 nm with 100% purity, and x=0.645 and y=0.357. The luminance for the Tb-doped film was 72 cd/m 2 with a dominant wavelength of 547 nm and 77% purity.