Effect of Er doping on optical band gap energy of TiO2 thin films prepared by spin coating

In order to evaluate the effect of Er doping in the range of 0–1.0 mol% on optical indirect band gap energy (E_g) of the film, the Er-doped TiO₂ (Er-TiO₂) thin films were spin-coated onto fluorine-doped SnO₂ coated (FTO) glasses. Glancing angle X-ray diffraction (GAXRD) results indicated that the films whose thickness was 550 nm consisted of pure anatase and FTO substrate. The anatase (101) TiO₂ peaks became broader and weaker with the rise in Er content. The apparent crystallite size decreased from 12 nm to 10 nm with increasing the amount of Er from 0 mol% to 1.0 mol%. UV–vis spectrophotometry showed that the values of E_g decreased from 3.25 eV to 2.81 eV with the increase of Er doping from 0 to 0.7 mol%, but changed to 2.89 eV when Er content was 1.0 mol%. The reduction in E_g might be attributed to electron and/or hole trapping at the donor and acceptor levels in the TiO₂ band structure.     

Thermoluminescence (TL) properties of Al2O3: C,Mg exposed to cobalt-60 gamma radiation doses

TL characteristics of powder form of Al₂O₃ doped with 0.1 mol% carbon and co-doped with different magnesium concentrations of 0.1 mol% and 0.2 mol% exposed to Cobalt-60 gamma ray at doses ranging from 5 Gy to 70 Gy were investigated. The recorded glow curves consist a dominant peak at 180 °C for a heating rate of 1 °C s⁻¹. The TL sample with 0.2 mol% Mg concentration have higher response compared to the sample with 0.1 mol% Mg concentration for a delivered dose of 5 Gy. The TL response has linear relationship with delivered dose for both samples. The TL sensitivity was found as 277.9 nC mg⁻¹ Gy⁻¹ for the sample with Mg concentration 0.2 mol% and 128.2 nC mg⁻¹ Gy⁻¹ for 0.1 mol% Mg. However, the sample with 0.1 mol% Mg concentration has better fading properties compared to the sample with 0.2 mol% Mg concentration. Both samples show good reproducibility with value less than 13%. The experimental value of effective atomic number, Z_eff is 9.21 and 9.44 for the sample with Mg concentration 0.1% mol and 0.2% mol, respectively, which are near to Z_eff of bone with a value of about 11.6.     

Synthesis,Structure, and Thermophysical Properties of Pb10 – xBix(GeO4)2 + xVO4)4 – x (x = 0–3) in the Temperature Range of 350–950 K

Physics of the Solid State - The Pb10 – xBix(GeO4)2 + x(VO4)4 – x (x = 0–3) compounds with an apatite structure have been...     

Mechanoluminescence characterisation of γ-irradiated (KNa)Br:Ce3+ phosphor

The mechanoluminescence (ML) of γ-irradiated coloured powder of (KNa)Br:Ce(0.1–10 mol%) phosphor is reported in this paper. The samples are prepared by wet chemical method. The ML intensities are found to be dependent on concentrations of Ce³⁺ ion and γ-rays radiation dose. The variation of peak ML intensity of (KNa)Br:Ce(0.5 mol%) with different γ-rays dose is found as linear up to 2.5 kGy high dose from 0.08 kGy, whereas for the KBr:Ce(0.5 mol%) and NaBr:Ce(0.5 mol%) samples the ML intensities increases sublinearly. The prepared sample shows minimum fading in ML intensity. The ML characterisation shows the good linearity, less fading and simple ML glow curve structure, thus the prepared material may be useful for radiation dosimetry.     

Development of ceria-doped zirconia electrolytes with high toughness and ionic conductivity

Development of Y₂O₃ stabilized ZrO₂ electrolytes for solid oxide fuel cell with better mechanical properties was attempted. 3 mol% Y₂O₃ stabilized ZrO₂ doped with 3–15 mol% CeO₂ was investigated in the present work. The results reveal that the toughness and the bending strength of 3–6 mol% CeO₂ doped 3 mol% Y₂O₃–ZrO₂ are much higher than that of 8 mol% Y₂O₃–ZrO₂. The best ionic conductivity observed in 6 mol% ceria-doped 3 mol% Y₂O₃–ZrO₂ electrolyte is better than that of 8 mol% Y₂O₃–ZrO₂ at 800 °C, which indicates the possibility of developing ZrO₂-based electrolyte with enhanced toughness.     

Haven Correlation Parameter for Diffusion of Fluorine in Superionic Conductors La1 – ySryF3 – y

Physics of the Solid State - The processes of electric charge transfer (conductivity) and mass transfer (diffusion) in La1 ‒ ySryF3 – y superionic...     

Impedance studies on bismuth-ruthenate-based electrodes

Doped bismuth ruthenates and bismuth ruthenate-stabilized bismuth oxide composites were studied as prospective cathode material for solid oxide fuel cells. Symmetric cells were fabricated on gadolinium-doped ceria electrolytes and studied by electrochemical impedance spectroscopy. Ca- and Ag-doped bismuth ruthenate electrodes (5–10 mol%) showed the same characteristic frequency as undoped bismuth ruthenate but with higher activation energy and slightly better performance above ∼550 °C. At 700 °C, area-specific resistance (ASR) of undoped, 5 mol% Ca and 5 mol% Sr-doped bismuth ruthenate electrode was 1.45, 1.24, and 1.41  Ωcm², respectively. The change in ASR as a function of oxygen partial pressure and current bias suggests that the rate-limiting steps for oxygen reduction in bismuth ruthenate systems are charge transfer and surface diffusion of dissociatively adsorbed oxygen to triple phase boundaries. Introduction of the erbia-stabilized bismuth oxide (ESB) phase reduced both the rate-limiting steps resulting in much improved electrode performance. At 700 °C, composite electrodes containing 31.25–43.75 wt% ESB exhibited an ASR of 0.08–0.11 Ωcm².     

H/D Isotope Effect in the Conductivity of CaZr1 – xScxO3 – α in Reducing Atmospheres

Physics of the Solid State - The ionic (proton and deuteron) conductivity of the system CaZr1 – xScxO3 – α (x = 0.03–0.20) is studied...     

Martensitic Transformation,Magnetotransport Properties,and Magnetocaloric Effect in Ni47 – xMn42 + xIn11 Alloys (0 ≤ x ≤ 2)

Physics of the Solid State - The structure, electrical and magnetic properties of Ni47 – xMn42 + xIn11 (0 ≤ x ≤ 2) alloys upon changing the...     

Synthesis and electrochemical performance of P2-Na0.67AlxCo1-xO2 (0.0 ≤ × ≤ 0.5) nanopowders for sodium-ion capacitors

Ionics - Layered P2-Na0.67Al x Co 1-x O2 (0.0 ≤ × ≤ 0.5) nanopowders were prepared by solution combustion process. These nanopowders were...     

Theoretical Approach to Investigation of the Magnetic and Magnetocaloric Properties of Heusler Ni–Mn–Ga Alloys

Physics of the Solid State - The magnetic and magnetocaloric properties of Heusler Ni2 + xMn1 – xGa alloys (x = 0.16, 0.18, and 0.3) have been studied...     

Effect of Cobalt on the Crystal Structure and Magnetism of Electron-Doped Sr0.8Ce0.2MnO3 Oxide

Physics of the Solid State - The Sr0.8Ce0.2Mn1 – yCoyO3 – δ (y = 0.2, 0.3, 0.4, 0.5, and 0.6) complex oxides with the perovskite structure...     

Photothermal Effect of Infrared (808 nm) Laser Radiation and Gold Nanoparticles in Different Modifications on S. aureus

Optics and Spectroscopy - A comparative study of the effect of infrared laser radiation (808 nm) of different power density on Staphylococcus aureus 209 P,...     

Resonant energy transfer and cross relaxation between Sm3+ ions in LiYF4 crystals

Luminescence decay curves of Sm³⁺ ions in LiYF₄ crystals doped with 1, 5 and 10 mol% Sm³⁺ are multi-exponential, whereas that in a LiYF₄ crystal doped with 0.1 mol% Sm³⁺ is well approximated by a single exponential function with a decay time of 4.8 ms. The average luminescence decay times decrease from 4.8 to 0.60 ms with the increasing Sm³⁺ concentrations between 1 and 10 mol%. The decay curves for all crystals are found to be almost independent of the temperature between 15 and 300 K. The decrease of the decay times for the higher Sm³⁺ concentrations indicates energy transfer between two Sm³⁺ ions. Taking the crystal structure of LiYF₄ into account, it is deduced that a single-step energy transfer process for the 1 and 5 mol% Sm³⁺ concentrations occurs from a Sm³⁺ ion at the origin of (0 0 0) to one of the Sm³⁺ ions substituting for the first nearest neighbor Y³⁺ sites and beyond within a sphere with an approximate radius of less than 0.7 nm. On the other hand, a multi-step energy transfer process dominates for the highest concentration (10 mol%) because the calculated average distance between two Sm³⁺ ions in the 10 mol% Sm³⁺ sample is comparable with the migration length of the single-step energy transfer process estimated from the 1 and 5 mol% Sm³⁺ samples.     

Ab Initio Study of the Structural Properties of the Co–Ni–Sn Heusler Alloys

Physics of the Solid State - The ab initio investigations of the structural and magnetic properties of the Co2Ni1 + xSn1 – x (x = 0,...     

Anomalous Hall Effect in Frustrated Magnets

Physics of the Solid State - Comparative analysis of Hall effect in substitutional solid solutions Ho0.5Lu0.5B12, Mn1 – xFexSi (0 ≤ x ≤ 1) and...     

Production of the 186mRe Isomer in Nuclear Reactors

Physics of Atomic Nuclei - To provide experiments on stimulation of de-excitation of the isomer state of the 186mRe nucleus (isomer half-life T1/2 = 2 × 105 yr) with...     

Radiative Constants in the W VII Ion Spectrum

Optics and Spectroscopy - The probabilities of the 4 f 135p66p + 4 f 145p56p – 4 f 136s, 4 f 137s radiative transitions...     

Observation of ferromagnetism and anomalous Hall effect in laser-deposited chromium-doped indium tin oxide films

We report on the structural, magnetic, and magnetotransport characteristics of Cr-doped indium tin oxide (ITO) films grown on SiO₂/Si substrates by pulsed laser deposition. Structural analysis clearly indicates that homogeneous films of bixbyite structure are grown without any detectable formation of secondary phases up to 20 mol% Cr doping. The carrier concentration is found to decrease with Cr ion addition, displaying a change in the conduction type from n-type to p-type around 15 mol% Cr doping. Room temperature ferromagnetism is observed, with saturation magnetization of ∼0.7 emu/cm³, remnant magnetization of ∼0.2 emu/cm³ and coercive field of ∼30 Oe for 5 mol% Cr-doped ITO. Magnetotransport measurements reveal the unique feature of diluted magnetic semiconductors, in particular, an anomalous Hall effect governed by electron doping, which indicates the intrinsic nature of ferromagnetism in Cr-doped ITO. These results suggest that Cr-doped ITO could be promising for semiconductor spin electronics devices.