Effect Of Tb Doping Research Articles

Studies on the effect of Tb doping on the structural and optical properties of La2(WO4)3 nanoparticles

Pristine and terbium ion-doped lanthanum tungstate nanoparticles were synthesized by the chemical precipitation method. In the present work, the effect of Tb doping on the structural and optical properties of lanthanum tungstate nanoparticles is studied. The structure and surface morphology of the prepared samples were analysed using the X-ray diffraction technique and scanning electron microscopy technique. Both the samples exhibit monoclinic scheelite structure. The optical properties of the samples were studied using UV–Visible absorption spectroscopy and photoluminescence spectroscopy. By Tb ion doping, the optical bandgap value reduces and the colour of emission of the sample changes from blue to green region.

The effect of Tb doping on the structural and magnetic properties of ZnO nanoparticles

Rare earth ions when incorporated in a semiconductor oxide lattice at nanoscale regime can affect the structural, optical as well as the magnetic properties of semiconductor host lattice. The change observed in the properties of the host lattice is due to the interaction between the dopant ions and host crystal. The structural and the morphological properties of Tb3+doped ZnO nanoparticles were studied using XRD, X-ray photoelectron spectroscopy and AFM studies. These experiments were performed on the doped nanoparticles to analyze the defects generated in the ZnO host lattice when a rare earth ion having ionic radii greater than that of Zn ion is doped in the ZnO nanoparticles. EDX measurement was used to estimate the elemental composition. An analysis of the XRD peak profile of the undoped and doped ZnO nanoparticle samples were done to evaluate the dislocation densities and the surface area. Both the parameters show an increase up to a certain concentration of Tb, which reveals the increase in the surface defects when Tb is introduced in ZnO host lattice. The strain calculated using Uniform deformation model from the XRD data also show an increase in the stress with the increase in Tb concentration which confirms the deformation of the host lattice. The magnetic study performed on the Pure ZnO nanoparticles shows a diamagnetic behaviour, while, Tb-doped ZnO nanoparticles exhibits room temperature ferromagnetism. The correlation between defects generated upon Tb-doping to the observed ferromagnetism, in the synthesized nanoparticles, has been reported.

The effects of Tb doping on the negative and positive magnetocaloric effects of Mn3Ga1−xTbxC (0.02 ≤ x ≤ 0.05)

Generally, researchers focus on the great negative magnetocaloric effect (NMCE) rather than the positive magnetocaloric effect (PMCE) in Mn3GaC. Here, we prepared Mn3Ga1−xTbxC composites with a partial substitution of Ga by Tb. Tb doping expands the canted-ferromagnetic phase (CFM) between the anti-ferromagnetic and ferromagnetic phase in Mn3Ga0.97Tb0.03C. The CFM phase can be as a boundary to separate the NMCE from PMCE. It is possible to combine the NMCE and PMCE for refrigeration. Compared with NMCE in Mn3GaC, NMCE–PMCE combination in Mn3Ga0.97Tb0.03C displays a much larger operating temperature range without loss of magnetic entropy changes. Therefore, the NMCE–PMCE combination is valuable for improving the operating temperature range of magnetocaloric effect materials. It also provides a new idea for refrigeration applications.

Noticeable enhancement in NH3 sensing performance of nebulizer spray pyrolysis deposited SnO2 thin films: An effect of Tb doping

Rare metal Terbium (Tb) doped SnO 2 (SnO 2 :Tb) films were fabricated via spray pyrolyzed method with different doping concentrations. The effects of terbium doping concentration on its microstructural, optical, photoluminescence , and room temperature ammonia vapor sensing properties were reported. The crystallite size of the prepared Tb-doped tin oxide films decreases with an increase in doping concentrations. The obtained crystallite size ranges from ~ 12 – 9 nm. The terbium incorporation was confirmed by EDS and elemental mapping. The bandgap values are enhanced as the concentration of Tb doping increases. The high gas response of 79% with fast response/recovery of 31/11 s , respectively is reported for 25 ppm of ammonia at room temperature for 5% Tb doped sample. The gas sensing cycle test shows the excellent sensitive behavior of the films without any decrease upon 5 repeated cycles. The stability of the sample was also checked for a corresponding Tb 5% doped sample, which revealed a stable response even for 50 days. • Novel SnO 2 :Tb thin films were fabricated facilely by nebulizer spray pyrolysis technique. • XRD study confirm monophasic rutile tetragonal films fabrication at all Tb contents. • Energy gap was enhanced from 3.63 to 3.76 eV on Tb doping in SnO 2 . • The highest response/quick recovery time of 31s/11s was noticed for 5 wt% SnO 2 :Tb films at 300K. • The stability of 5 wt% SnO 2 :Tb film was tested and noticed a stable response even for 50 days.

Fabrication and magnetic properties of Tb-doped multiphase Pr-Tb-Fe-B magnetic nanowire arrays

Tb-doped multiphase Pr-Tb-Fe-B magnetic nanowire arrays were prepared into anodic aluminum oxide (AAO) template by direct current (DC) electrodeposition. The effect of Tb doping on the phase composition, microstructure and magnetic properties of Pr-Tb-Fe-B composite nanowires was characterized and analyzed, and all technical parameters of the electrodeposition process and nanowires growth for Pr-Tb-Fe-B nanowire arrays were illustrated and optimized. The results show that with the addition of Tb element, the Pr, Tb atoms exist in solid solution form in the as-deposited Pr-Tb-Fe-B nanowires and the nanowires are composed of FeB and Fe2B phases, showing soft magnetic properties. After annealing at 873 K for 2 h, Pr-Tb-Fe-B nanowires are recrystallized. Pr, Tb atoms are precipitated and part of Pr element substituted by Tb and enter the main phase to form the second hard magnetic phase (Pr,Tb)2Fe14B, so multiphase composite nanowires composed of double main hard magnetic phases (Pr2Fe14B + Tb2Fe14B) were carried out. It is indicated by test that the coercivity of the annealed Pr-Tb-Fe-B nanowires are significantly improved by the microstructure of double main hard magnetic phases, reaching 2376.32 Oe.

The effect of Tb doping on the magnetic properties and microstructure of a TbNdFeCoB/Fe7Co3 nanocomposite permanent magnet

Melt-spun NdFeB-type nanocomposite magnetic materials are important in a number of applications, including electromagnetic sensors, magnetic resonance imaging, and voice coil motors. Herein we investigated the magnetic properties and microstructures of melt-spun TbxNd10−xFe80Co4B6/Fe7Co3 (x = 0.1, 0.2, and 0.3) ribbons by means of x-ray diffractometry, scanning electron microscopy, and magnetization experiments. Tb doping resulted in the formation of a 2:14:1 phase with a higher anisotropy field, which suppressed the separation of Fe7Co3 branch crystals and improved the magnetic properties of the material. Optimum magnetic properties that include a remanence (Jr) of 0.62 T, a coercivity (Hci) of 612.0 kA m−1, and a maximum magnetic energy product ((BH)max) of 94.9 kJ m−3 were obtained for the annealed Tb0.3Nd9.7Fe80Co4B6/Fe7Co3 ribbon. Furthermore, the effective anisotropy constant, and the saturation magnetization, in the nanocomposite were determined by the LATS (law of approach to saturation) method. In this study, the values of and were found to lie between those of hard and soft magnetic phases, consistent with the exchange-coupling concept.

Investigation on physical properties of CdO thin films affected by Tb doping for optoelectronics

Thin films of Tb-doped CdO were grown on FTO substrates using the sol–gel-spin coater technique. XRD studies confirmed the polycrystalline cubic growth of the films with a (200) preferential orientation. XRD analysis was used to estimate the crystallite sizes, dislocation density, and microstrain values, and found that they are highly dependent on the doping percentage. Homogeneous distributions of the nano-gains were observed from the AFM studies. Energy-dispersive spectroscopy and mapping analyses were used for the uniform elemental composition confirmation. All the films displayed high transmission reaching nearly 80% in the visible spectrum and the effect of Tb doping was very clear by corresponding systematic increase in intensities. The direct band-gap values were estimated from the Tauc plots and are found to be highly tunable based on the doping percentage, which was varying between 2.79 and 2.91 eV. The refractive index and extinction coefficient values are lies between 1.8 and 2.5 and 0.44 to 0.82. The $${\chi ^{(1)}}$$ values are found to be varying between of 0.05 to 0.45 within the range 1–4 eV. This suggests all the linear and nonlinear optical properties of the present samples can be tailored for the various applications by the doping.

Effect of Tb Doping on Structural and Optical Properties of (Cd0.8-Zn0.2)S Films Deposited Through a Chemical Route

Tb-doped (Cd0.8-Zn0.2)S films have been prepared on glass substrates at 60°C by a chemical bath deposition technique. The effect of variation in the molar concentration of terbium (Tb) on the optical properties of the deposited films has been investigated and is discussed. The films have been characterized through x-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis absorption and photoluminescence (PL) emission spectral studies. Prominent diffraction lines of CdS and ZnS with maximum orientation towards (111)c plane of CdS are observed in XRD patterns. Particle sizes calculated from XRD studies using Scherrer’s formula are found to be in the nano-range. The SEM micrographs of bulk film showed a layered structure, while a honey-comb structure with thickness of layers in the nano-range is seen for the deposited films. From the optical absorption spectra, a blue shift in the absorption edge is distinctly observed in the nanocrystalline films as compared to bulk film, suggesting the involvement of a quantum confinement effect. PL emission spectra showed distinct emission peaks for bulk and nanocrystalline films. PL emissions due to transitions within Tb3+ levels are also observed. The characteristic green emission peak due to 5D4-7F2 transition in Tb at 620 nm is observed in all three cases. Various studies suggest that the deposited films have potential applications in photo-electronic devices.

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).

Effect of Tb3+ ion substitution on structural, optical and magnetic properties of CdS nanoparticles

Cd1−xTbxS (x = 0.00, 0.05, 0.10, 0.15) nanoparticles were synthesized by hydrothermal technique. The effect of Tb-doping on structural, optical and magnetic properties were studied. The X-ray diffraction (XRD) confirmed wurtzite phase without any impurity. HR-TEM micrographs revealed the particle size of ~ 18 nm with spherical morphology. Band gap calculated from UV–Visible absorption spectra showed an initial decrease from 2.49 eV (x = 0) to 2.45 eV (x = 0.10). Further, increasing Tb-doping to x = 0.15 band gap increased to 2.54 eV. Photoluminescence emission spectra showed peaks at 430 and 490 nm for x = 0 and 0.05 which corresponds to blue emission. Further increase in Tb doping, peaks found to be quenched. Peak at 530 nm is due to green emission and shifted to higher wavelength with Tb-doping. Magnetic analysis confirmed ferromagnetism in both undoped and Tb-doped nanoparticles. Saturation magnetization found to decrease upto x = 0.10 and increased for x = 0.15.

Effect of Tb-doping on structural, magnetic and optical properties of BiFeO3 films prepared by chemical solution deposition

Single-phase multiferroic Bi1-xTbxFeO3 (xBTFO, x=0.00, 0.03, 0.06 and 0.09) films were deposited on quartz substrates by chemical solution deposition. X-ray diffraction patterns indicate that all films exhibit a distorted pseudo-tetragonal perovskite structure with a high degree of (110) preferred orientation. The Tb-doping at A-site of BiFeO3 (BFO) results in lattice contraction, improves surface morphology and reduces the average grain size of the films. One A mode and five E modes of films are observed in Raman scattering spectra, and the position of A mode shifts to higher wavenumber with the increasing of x due to the enhanced Bi–O covalent by Tb doping. With increasing x from 0.00 to 0.09, the saturation magnetization of xBTFO films increases and can be expressed by Ms=(34.6x+1.1) emu/cm−3, originating from different bond interactions between 4f, 5d orbitals of Tb–O and 6p orbitals of Bi–O. Compared with BFO film, the band gap of xBTFO films decreases, which is mainly due to the increased the tailing of the conduction band edge into the band-gap, which is leading to decreasing the band gap.

Crystal structure and magnetic properties of Tb-doped Ru-1222 ruthenocuprates

The effects of Tb doping on the structural, superconducting, and magnetic properties of (Ru0.9Nb0.1)Sr2(Gd1.34−xTbxCe0.66)Cu2Oz and RuSr2(Eu1.34−xTbxCe0.66)Cu2Oz (x=0, 0.34) systems were investigated. It was found that Tb doping in both systems results in a significant suppression of superconductivity and an enhancement of the magnetic ordering temperature, as well as an enhancement of the weak-ferromagnetic component of field-cooled magnetization. The Rietveld refinements of the X-ray diffraction data at room temperature showed that both a and c lattice parameters decrease and the rotation angle of the RuO6 octahedron around the crystallographic c-axis decreases by Tb doping in both systems. The superconducting and magnetic behaviors induced by the Tb doping are discussed in conjunction with the change in hole concentration and the local structural changes in the Ru sublattice induced by Tb doping.

Investigation of Tb-doping on structural transition and multiferroic properties of BiFeO3 thin films

Pure BiFeO3 (BFO) and Bi1−xTbxFeO3 (BTFO) thin films were successfully prepared on FTO (fluorine doped tin oxide) substrates by the sol–gel spin-coating method. The effects of Tb-doping on the structural transition, leakage current, and dielectric and multiferroic properties of the BTFO thin films have been investigated systematically. XRD, Rietveld refinement and Raman spectroscopy results clearly reveal that a structural transition occurs from the rhombohedral (R3c:H) to the biphasic structure (R3c:H+R-3m:R) with Tb-doping. The leakage current density of BTFOx=0.10 thin film is two orders lower than that of the pure BFO, i.e. 5.1×10−7A/cm2 at 100kV/cm. Furthermore, the electrical conduction mechanism of the BTFO thin films is dominated by space-charge-limited conduction. The two-phase coexistence of BTFOx=0.10 gives rise to the superior ferroelectric (2Pr=135.1μC/cm2) and the enhanced ferromagnetic properties (Ms=6.3emu/cm3). The optimal performance of the BTFO thin films is mainly attributed to the biphasic structure and the distorted deformation of FeO6 octahedra.

Effect of Tb Doping on Structural and Electrical Properties of BiFeO3 Thin Films Prepared by Sol–Gel Technique

Bi1−xTbxFeO3 thin films were prepared on SnO2 (fluorine doped tin oxide) substrates by a sol–gel method. The structural and electrical properties of the BiFeO3 thin films were characterized and tested. The results indicated that the diffraction peak of the Tb-doped BiFeO3 films was shifted towards right as the doping amounts were increased. The structure was transformed from the rhombohedral to tetragonal/orthorhombic phase. The Bi0.89Tb0.11FeO3 thin film showed the well-developed P–E loops, which enhanced remnant polarization (Pr = 88.05 μC/cm2) at room temperature. The dielectric constant and dielectric loss of Bi0.89Tb0.11FeO3 thin film at 100 kHz were 185 and 0.018, respectively. Furthermore, the Bi0.89Tb0.11FeO3 thin film showed a relatively low leakage current density of 2.07 × 10−5 A/cm2 at an applied electric field of 150 kV/cm. The X-ray photoelectron spectroscopy (XPS) spectra indicated that the presence of Fe2+ ions in the Bi0.89Tb0.11FeO3 thin film was less than that in the pure BiFeO3.

Size-dependent magnetic and dielectric properties of Tb-doped BiFeO3 nanoparticles

Pure and Tb-doped BiFeO3 nanoparticles have been prepared by sol–gel method. The nanoparticles of different size have been obtained by the calcination of synthesized nanoparticles at different temperatures. The effects of Tb doping and size of nanoparticles on the crystal structure, magnetic and electrical properties have been studied. The partial substitution of Tb ions results in a change from rhombohedral (x = 0) to orthorhombic (x = 0.15) structure. The average crystallite size varies from 14 to 40 nm. The synthesized nanoparticles possess ferromagnetic behavior. The saturation magnetization is high for the Tb-doped BiFeO3 nanoparticles calcined at 450 °C, and it decrease with the increase of size. The dielectric constant and loss improve with Tb doping and size. The relaxation behavior of dielectric loss is of Debye type. The dielectric loss peaks shift to the lower frequencies with increase in the size of Tb-doped BiFeO3 nanoparticles.

Room temperature ferromagnetism in Tb-doped ZnO dilute magnetic semiconducting nanoparticles

Pure and Tb-doped ZnO nanoparticles have been synthesized by chemical co-precipitation method. The transmission electron microscopy study reveals the spherical morphology of synthesized nanoparticles with average particle size 14–18 nm. The effect of Tb-doping on structural, optical and magnetic properties has been studied. X-ray diffraction shows that pure and Tb-ZnO nanoparticles exhibit wurtzite structure having hexagonal phase with primitive unit cell. It further reveals that there is no effect of Tb-doping on the X-ray diffraction pattern up to 2 % doping, however, higher doping concentration result in accumulation of Tb on ZnO surface. Photoluminescence spectra reveal that the doping Tb in ZnO changes crystallographic structure generating non-radiative oxygen vacancies. Three emission peaks located around 423, 485 and 515 nm has been observed. Pure ZnO nanoparticles show diamagnetic character, however, Tb-doped ZnO nanoparticles exhibit room temperature ferromagnetism. The correlation between defects generated upon Tb-doping to the observed ferromagnetism, in the synthesized nanoparticles, has been reported.

Multiferroic properties of Tb-doped BiFeO3 nanowires

Nanoscale, multifunctional, multiferroic materials possess strong magnetoelectric coupling (ME), open exciting multitudinous ways for designing future nanoelectronic and spintronic device applications. Bulk nanowires (100 nm), pure, and Tb-doped BiFeO3 multiferroic nanowires (20 nm) have been synthesized by colloidal dispersion template-assisted technique. The effects of Tb-doping and size of synthesized nanowires on structural, electrical, magnetic, dielectric, and magnetodielectric properties have been investigated. X-ray diffraction study reveals that doping of Tb in BiFeO3 nanowires leads to structural transformation from rhombohedral to orthorhombic. X-ray photoemission analysis confirms the +3 oxidation state of Fe and high purity of samples. Bulk nanowires exhibit antiferromagnetic characteristics, whereas the Tb-doped BiFeO3 nanowires show ferromagnetic character. Moreover, with increase in Tb concentration, the saturation magnetization increases. Temperature-dependent magnetization study suggests their size-dependent ferro and ferri-magnetic behavior. Polarization versus electric field (P–E) study reveals that pure BiFeO3 nanowires possess elliptical loop; however, doping of Tb results in rectangular loop— portentous good ferroelectric properties. All synthesized samples exhibit frequency-dependent dielectric constant which decreases with increase in frequency and remains fairly constant at higher frequencies. Leakage current density decreases with increase in Tb concentration, and has been found to be three orders of magnitude less than those of bulk BiFeO3 nanowires. The ME coupling in synthesized nanowires was estimated by measuring magnetodielectric. A very high value of ME, 7.2 %, has been found for 15 % Tb-doped BiFeO3 nanowires. In this communication, we, for the first time, report new cue on size-dependent Tb-doped BiFeO3 nanowires, which may be further used to explore its technological device applications.

Spin reorientation and spin-flop transition in multiferroic manganites Y1–xTbxMnO3 (x = 0, 0.1, 0.2) single crystals

We investigated the structure and magnetic properties of the multiferroic hexagonal manganite Y1−xTbxMnO3 (x = 0, 0.1, 0.2) single crystals. At 23 K, a Mn spin reorientation transition, which is not reported in the parent compound YMnO3, is observed in Y0.8Tb0.2MnO3. At a lower temperature, another new transition is observed in the doping system, which is attributed to the formation of long range antiferromagntic order of the doped Tb3+ moments. Based on the experimental results, we suggest that the effect of Tb doping is to bring about the increase of the Mn-O-Mn bond angle and the relief of the magnetic frustration. With increasing the doping level, for x = 0.2, when a magnetic field is applied parallel to the c axis, the field induced spin-flop transition is appeared, which indicates the reorientation of the Mn3+ moments along with the field-induced ferromagnetic ordering of the Tb3+ moments. These results suggest that the possibility of the Tb doping can change the magnetic structure and ferroelectricity properties of YMnO3.

Effect of Tb doping on electric and magnetic behavior of BiFeO3 thin films

The effect of Tb doping on crystal structure and electric and magnetic behavior of BiFeO3 thin films prepared via a solution processing on (111)Pt∕Ti∕SiO2∕Si substrates was studied. The substitution of Bi ions by a small amount of Tb ions could stabilize the valence of Fe3+ in BiFeO3 thin films, and as indicated by transmission electron microscope images and largely reduced leakage current in comparison with pure BiFeO3 thin films, the quality of the films was improved by Tb doping. Electric and magnetic behavior of Tb-doped BiFeO3 films was investigated with employing La-doped BiFeO3 films as comparison. Large enhancement in both remnant and saturation polarization and the polarization switching were observed in Tb-doped BiFeO3 films, while the inhomogeneous spin-modulated magnetic structure of BiFeO3 was not modified through Tb substitution but by La substitution.

Effects of Tb doping on the photoluminescence of Y 2O 3:Tb nanophosphors

The effects of Tb doping on the photoluminescence (PL) of Y 2O 3:Tb nanophosphors have been investigated. Nanophosphors were prepared by the glycine–nitrate solution combustion technique using yttria and terbia powders as precursors. PL excitation spectra at room temperature consist of two overlapping bands centered at 277 and 304 nm, whereas emission spectra comprise several groups of lines corresponding to the 5D 4→ 7F J ( J=1–6) 4f electronic transitions of the Tb +3 ions. A direct comparison of nanophosphor and bulk concentration-quenching curves was obtained by annealing the nanophosphor powder and converting it to bulk material without altering the Tb concentration. The peak in the nanophosphor concentration-quenching curve occurs at a concentration ∼3 times higher than that of the bulk.