The impact of Eu3+ ion substitution on dielectric properties of Y3-xEuxAl5O12 (0.00x0.10) ceramics

Baykal, Abdulhadi/0000-0002-5205-0937; almessiere, munirah a/0000-0003-1651-3591; UNAL, Bayram/0000-0003-2025-9848WOS: 000460143900055This study reported the effect of Eu substitutions on the conductivity and dielectric properties of Y3-xEuxAl5O12 (0.0x0.1), YAG:xEu(3+). All products were fabricated by solid state route. The formation of YAG was approved through X-ray diffraction powder diffraction and high-resolution transmission electron microscope. It was found that the lattice parameters are increasing with increase the substitution content due to the difference in ionic radii between Y3+ and Eu3+. Electrical and dielectric properties of YAG (Y3Al5O12) and YAG:xEu(3+) ceramics were investigated extensively for a variety of concentrations (0.00x0.1) of the substitutional Eu3+ ion from the 4f lanthanide group. The temperature dependence of dielectric loss, dielectric constant, loss tangent and ac/dc conductivity were examined up to 5.0MHz to understand the electrical and dielectric properties for both doped and undoped YAG ceramics. The experimental results revealed that Eu3+ ion substitutions (especially x=0.05) in YAG ceramics meaningfully influence the lossy mechanisms, conductivity and dielectric constant which is probably due to the contribution to the conduction mechanism of the 4f-Eu and 3d-Al ions. So, this can be incorporated at the exceptional sites of both O-h (octahedral) and T-d (tetrahedral) symmetries in YAG: xEu(3+) ceramics.Institute for Research & Medical Consultations (IRMC) of Imam Abdulrahman Bin Faysal University [2018-IRMC-S-1]Authors are grateful to the Institute for Research & Medical Consultations (IRMC) of Imam Abdulrahman Bin Faysal University for the financial assistance to pursue this research (Grant No: 2018-IRMC-S-1). The technical assistance provided by Core Labs of King Abdullah University of Science and Technology (KAUST) are highly appreciated

The impact of Eu3+ ion substitution on dielectric properties of Y3-xEuxAl5O12 (0.00x0.10) ceramics

Baykal, Abdulhadi/0000-0002-5205-0937; almessiere, munirah a/0000-0003-1651-3591; UNAL, Bayram/0000-0003-2025-9848WOS: 000460143900055This study reported the effect of Eu substitutions on the conductivity and dielectric properties of Y3-xEuxAl5O12 (0.0x0.1), YAG:xEu(3+). All products were fabricated by solid state route. The formation of YAG was approved through X-ray diffraction powder diffraction and high-resolution transmission electron microscope. It was found that the lattice parameters are increasing with increase the substitution content due to the difference in ionic radii between Y3+ and Eu3+. Electrical and dielectric properties of YAG (Y3Al5O12) and YAG:xEu(3+) ceramics were investigated extensively for a variety of concentrations (0.00x0.1) of the substitutional Eu3+ ion from the 4f lanthanide group. The temperature dependence of dielectric loss, dielectric constant, loss tangent and ac/dc conductivity were examined up to 5.0MHz to understand the electrical and dielectric properties for both doped and undoped YAG ceramics. The experimental results revealed that Eu3+ ion substitutions (especially x=0.05) in YAG ceramics meaningfully influence the lossy mechanisms, conductivity and dielectric constant which is probably due to the contribution to the conduction mechanism of the 4f-Eu and 3d-Al ions. So, this can be incorporated at the exceptional sites of both O-h (octahedral) and T-d (tetrahedral) symmetries in YAG: xEu(3+) ceramics.Institute for Research & Medical Consultations (IRMC) of Imam Abdulrahman Bin Faysal University [2018-IRMC-S-1]Authors are grateful to the Institute for Research & Medical Consultations (IRMC) of Imam Abdulrahman Bin Faysal University for the financial assistance to pursue this research (Grant No: 2018-IRMC-S-1). The technical assistance provided by Core Labs of King Abdullah University of Science and Technology (KAUST) are highly appreciated

A novel approach to produce monodisperse hollow pure silica spheres

In this work, we report an efficient method to produce pure hollow silica spheres (HSS) using phenyltrimethoxysilane (PTMS) compound. The production of HSS was carried out via hydrolysis of PTMS in the aqueous media and followed by a condensation reaction to form silica spheres with phenyl groups. The product was then calcined to remove phenyl groups and obtain pure silica spheres with >95% fine structure. The chemical nature of pure silica was confirmed by Fourier transforms infrared spectroscopy. The calcined HSS were stable beyond the temperature of 900 °C as confirmed by thermal gravimetric analysis (TGA). The calcined spheres preserved their spherical appearance and hollow core as shown by SEM and TEM micrographs. Interestingly, the average size of the spheres was reduced significantly after calcination from 760 to 510 nm, confirming further the removal of phenyl groups. The calcined HSS offered much higher surface area (As) when analysed by BET; As for calcined product was ∼406 and mere ∼4.8 m2/g for uncalcined HSS. Finally, drug release study of cisplatin/HSS showed over 45% of steady cumulative release for 72 h. The prepared HSS can be dispersed in water opening the possibility of many novel bio/non-bio applications. Keywords: Silica spheres, Hollow core, Calcination, Cisplatin, Drug deliver

Investigation of the impact of nano-sized wires and particles TiO2 on Y-123 superconductor performance

In the current investigation, we report the impact of TiO2 nanowires (NW) and nanoparticles (NP) addition on flux pinning and superconducting characteristics of YB2Cu3O7-d (Y-123 or YBCO) material. Specimens were produced through solid-state reaction (SSR) route. The microstructure of samples showed an almost regular dispersion of nanometer scale entities for NP-added samples and a distribution of nanowires inside the grain boundaries for NW-added samples. The Y-123 phase structure was maintained with the addition of TiO2 nano-entities up to 0.1 wt%. An improvement of superconducting properties was observed for samples added with 0.1 wt% of TiO2 nano-entities compared to non-added one. Among all the prepared samples, a considerable augmentation of critical current densities in the absence and in the existence of applied magnetic fields was obtained for 0.1 wt% TiO2 NP added samples. The possible flux pinning mechanisms and correlation between the shapes of nano-entities, structure and superconducting properties was studied and discussed. An important result of the current study is that there is an increase of effective pinning centers and a complete change of vortex pinning mechanisms; from the fluctuation in the Tc (?Tc) to the mean free path of the charge carriers (?l) for the 0.1 wt% TiO2 NP added sample compared to the non-added and 0.1 wt% TiO2 NW added samples. © 2018 Elsevier B.V.Instituto Antártico Uruguayo: 2017-IRMC-S-3, 2018-IRMC-S-2This work was supported by the Institute for Research and Medical Consultations (IRMC) of Imam Abdulrahman Bin Faisal University (IAU – Saudi Arabia) for the financial support through the projects number ( 2018-IRMC-S-2 ) and ( 2017-IRMC-S-3 )

Magnetic and structural characterization of Nb 3+ -substituted CoFe 2 O 4 nanoparticles

This study investigated the effect of Nb 3+ substitution on the magnetic and structural properties of CoFe 2 O 4 nanoparticles (NPs) synthesized by hydrothermal approach. The formation of a single phase of spinel ferrite was confirmed through X-ray powder diffraction, and crystallite sizes in the range 18–30 nm were observed. Moreover, it found that the Fourier transform infrared (FT-IR) spectra of the NPs included the main vibration bands of the spinel structure. The partially cubic structure was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The energy band gaps for CoNb x Fe 2-x O 4 were estimated to be in the range 0.48–0.53 eV for Nb 3+ content x = 0.0–0.10. Magnetization measurements at room temperature (RT; 300 K) and at 10 K were performed on spinel CoNb x Fe 2-x O 4 (0.00 ? x ? 0.10) NPs using a vibrating sample magnetometer (VSM). Nb 3+ doping significantly changed the magnetization and coercivity of the Co ferrite samples. RT hysteresis curves indicated well-defined ferrimagnetic behavior for all prepared NPs with saturation magnetization (M s ) in the range 44.45 – 49.40 emu/g and remanent magnetization (M r ) in the range 12.16 – 17.90 emu/g. The coercive field (H c ) is found to be equal 936 Oe and is decreased with Nb 3+ substitutions. However, hysteresis curves at 10 K showed finite remanent specific magnetization (1.90–6.70 emu/g) but significant asymmetric coercivity (715–2810 Oe), particularly for the Nb 3+ -doped samples. At 10 K, the magnetization values were 4–6 times smaller but symmetric coercivity field values were 2–3 times larger compared with the RT-VSM curves. The obtained magnetic parameters indicated the semi-hard magnetic character of the Co ferrite samples at low temperatures. © 2019 Elsevier Ltd and Techna Group S.r.l

Corrigendum to “The effect of Nb substitution on magnetic properties of BaFe12O19 nanohexaferrites” [Ceram. Int. 45 (2019) 1691–1697](S027288421832844X)(10.1016/j.ceramint.2018.10.048)

The authors regret that in the published version of this article two additional affiliation addresses were missing for the author A.V. Trukhanov. The affiliation additional addresses are: National University of Science and Technology MISiS, 119049, Moscow, Leninsky Prospekt, 4, Russia South Ural State University, 454080, Chelyabinsk, Lenin Prospect, 76, Russia The authors would like to apologise for any inconvenience caused. © 2018 Elsevier Ltd and Techna Group S.r.l