Article
Materials Science, Multidisciplinary
Bruna M. Silva, Joao Oliveira, Tiago Rebelo, Antonio Calianguila, Diogo Silva, Jorge Mendes, Bernardo G. Almeida
Summary: Multiferroic bilayer thin films composed of LiNbO3 and CoFe2O4 were fabricated by laser ablation. The LiNbO3 layer thickness was found to affect the structural, electric, and dielectric properties of the films. The mechanical interaction between the layers and the presence of point defects in the LiNbO3 layer resulted in strain effects that decreased as the LiNbO3 layer thickness increased. Thicker LiNbO3 layers exhibited bulk-like characteristics and a transition from polaronic to ionic conduction with increasing temperature, while thinner LiNbO3 layers displayed polaronic behavior up to higher temperatures due to the formation of bound polarons associated with lithium defects.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Physics, Applied
G. K. Herring, L. Hesselink
Summary: Typical x-ray detectors face a trade-off between resolution and quantum efficiency, while holographic x-ray detection using photorefractive materials can achieve both high resolution and high efficiency.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Sourabh Wajhal, S. K. Mishra, A. B. Shinde, P. S. R. Krishna, R. Mittal
Summary: Correlated disorder in (1-x)NaNbO3-(x)BaTiO3 solid solution with Ca substitution has been studied, showing enhanced dielectric constant and the competition and cooperation between polar and antiferrodistortive mode. Powder neutron diffraction data reveals changes in diffraction peaks, suggesting a structural phase transition and extended phase stability of functional ferroelectric phase at lower temperatures.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
Jiali Song, Zhi Wang, Yu Gao
Summary: Different annealing temperatures were used to prepare nanocrystalline Li0.35Ni0.3Fe2.35O4 ferrites through sol-gel auto-combustion method. The annealing temperature significantly affected the structure and magnetic properties of the synthesized Li-Ni ferrites, leading to an increase in grain size. The changes in saturation magnetization and coercivity were related to the occupation of ions in the crystal lattice and the size of the grains after annealing.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Zheng Cui, Guowei Deng, Pan Xu, Xiaoyang Liu, Min Yang, Qiliang Wang
Summary: In this study, doped and co-doped LaNbO4:RE3+ (RE = Eu, Eu/Tb, Tb) single crystals were prepared using a unique hydrothermal method. The crystal structure of LaNbO4:Eu3+/Tb3+ was refined using the Rietveld method, and the luminescence properties were analyzed. The results showed energy transfer between the host and doped Eu3+/Tb3+ ions, and emission colors could be varied by adjusting the concentration of dopant ions.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Mukesh Kumar Verma, Devinder Singh
Summary: The study focused on the impact of Li substitution in the La0.65Ca0.35-xLixMnO3 system on structural, magnetic, and transport properties. It was found that the phases exhibit transitions from paramagnetic to ferromagnetic state and from semiconductor to metal, with slight discrepancy between experimental and theoretical magnetic moments possibly due to magnetic inhomogeneity. Resistivity data suggested conduction in the phases is dominated by the adiabatic small polaron hopping (ASPH) model.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Chemistry, Physical
Lingyuan Gao, Robert B. Wexler, Ruixiang Fei, Andrew M. Rappe
Summary: Using first-principles calculations, this study investigates the ground-state structure, dielectric response, and optical properties of bulk proton-exchanged lithium niobate, a compound widely used in waveguides. Different ambient conditions result in the formation of dehydrated and rehydrated phases, which exhibit distinct dielectric constants and refractive indices compared to lithium niobate. The findings provide valuable insights into the structural and thermal characteristics of hydrogen niobate and its potential applications in waveguide devices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Inorganic & Nuclear
Roberto Koeferstein, Stefan G. Ebbinghaus
Summary: By adding LiNbO3 as a sintering aid, the sintering temperature can be reduced, grain growth can be improved, and high density ceramic bodies can be obtained. The addition of different amounts of LiNbO3 affects the phase transition temperature and microstructure. In contrast, using LiF as a sintering aid results in the formation of considerable amounts of secondary phases and lower relative density.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Materials Science, Multidisciplinary
Neil Sinclair, Daniel Oblak, Erhan Saglamyurek, Rufus L. Cone, Charles W. Thiel, Wolfgang Tittel
Summary: The study characterizes the optical coherence and energy-level properties of Tm3+ in a Ti4+ :LiNbO3 waveguide, finding consistency between indiffused Tm-3(+) :Ti-4(+) :LiNbO3 and bulk-doped Tm-3(+) :LiNbO3 crystal properties. These results support the use of rare-earth ions for integrated optical and quantum signal processing, complementing previous research in a narrower parameter space.
Article
Optics
Haijin Huang, Xu Han, Armandas Balcytis, Aditya Dubey, Andreas Boes, Thach G. G. Nguyen, Guanghui Ren, Mengxi Tan, Yonghui Tian, Arnan Mitchell
Summary: This paper presents a recirculating phase modulator that increases modulation efficiency by modulating the optical field multiple times in a non-resonant waveguide structure. By looping the light back, the modulator requires lower power and has potential applications in advanced tunable electro-optical devices.
Article
Materials Science, Multidisciplinary
Hesham M. H. Zakaly, H. A. Saudi, H. O. Tekin, M. Rashad, Shams A. M. Issa, Y. S. Rammah, A. Elazaka, M. M. Hessien, Antoaneta Ene
Summary: This study recycled ceramic and porcelain waste from Egypt to produce waste glass samples for nuclear radiation shielding applications, with the Waste32 sample containing 32 wt.% LiNbO3 showing the best shielding properties among the fabricated samples.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Physics, Condensed Matter
Muhammad Zain Yar, Muhammad Khalid, Muhammad Yasin, Kiran Naz, Muhammad Gul Bahar Ashiq, Muhammad Younas, Thamraa Alshahrani, Khaild I. Hussein, Khizar Bin Hassan, Bilal Ahmed, M. Mohamed Javid
Summary: The manganese-substituted nickel-rich lithium-cobalt oxide Li2Ni6MnxCo2-xO10 was successfully synthesized using the sol-gel autocombustion method. The structure and morphology of the material were characterized by XRD and SEM techniques, respectively. The prepared nanomaterial exhibited a hexagonal structure with a secondary phase. The average crystallite size was determined to be between 12 and 27 nm using different methods. SEM analysis showed the surface morphology and particle size distribution. The dielectric characteristics of the material were frequency-dependent, indicating suitability for high-frequency devices. Magnetic measurements revealed variations in saturation magnetization and coercivity with increasing Mn concentration. The obtained dielectric properties suggest potential applications in energy storage.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Multidisciplinary Sciences
Ofir Yesharim, Shaul Pearl, Joshua Foley-Comer, Irit Juwiler, Ady Arie
Summary: Nonlinear holography shapes the amplitude and phase of new harmonics using nonlinear processes, which has significant impact in various areas of optics. In this study, the concept of nonlinear holography is extended to the quantum regime, where the spatial quantum correlations of entangled photon pairs are directly shaped in two-dimensional patterned nonlinear photonic crystals. These quantum states exhibit quantum correlations and violate the Clauser-Horne-Shimony-Holt inequality, enabling entanglement-based quantum key distribution. This demonstration opens up possibilities for controllable on-chip quantum optics schemes using spatial degree of freedom.
Article
Nanoscience & Nanotechnology
Nilesh P. Barde, Sunil S. Shewale, Piyush S. Solanki, Nikesh A. Shah, Pranav P. Bardapurkar
Summary: Lithium ferrite nanoparticles dispersed in a silica matrix show promising applications due to their good dispersion and stability. XRD measurements and UV-Vis absorption spectra indicate significant changes in the structure and performance of the nanocomposites with increasing silica content. The use of complex impedance spectroscopy enables accurate modeling of the electrical properties of the materials.
SCRIPTA MATERIALIA
(2021)
Article
Optics
C. H. R. I. S. T. I. A. N. KIEssLER, H. A. U. K. E. Conradi, M. O. R. I. T. Z. Kleinert, V. I. K. T. O. R. Quiring, H. A. R. A. L. D. Herrmann, C. H. R. I. S. T. I. N. E. Silberhorn
Summary: A chip-size fully integrated fiber-coupled heralded single photon source (HSPS) module based on a hybrid integration of a nonlinear lithium niobate waveguide into a polymer board is presented. Photon pairs at 810 nm (signal) and 1550 nm (idler) are generated via parametric down-conversion pumped at 532 nm in the LiNbO3 waveguide. The module has a size of (2 x 1) cm2 and is fully fiber-coupled with one pump input fiber and two output fibers, achieving a heralded second-order correlation function of g(2) h = 0.05 with a heralding efficiency of & eta;h = 3.5% at low pump powers.
Article
Chemistry, Physical
Hasna Ltaief, Saida Ben Ali, Adel Mahroug, Valeria Ferretti, Manuel Pedro Fernandes Graca, Mohamed Belhouchet
Summary: A new copper compound [H2L]2(CuCl4(H2O)2).2Cl center dot 2H2O [ L = 3,3'- diaminodiphenylsulfone] was synthesized by slow evaporation method and characterized by various techniques. The compound crystallizes in the P-1 triclinic space group and shows a packing pattern with alternating organic and inorganic layers stabilized by hydrogen interactions. The compound exhibits optical absorption bands at 245, 308, and 554 nm, with indirect and direct gap energies of 1.54 and 1.64 eV, respectively. Thermal analysis (TGA and DSC) was also performed.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Article
Chemistry, Physical
Silvia R. Gavinho, Ana Sofia Padua, Isabel Sa-Nogueira, Jorge C. C. Silva, Joao P. Borges, Luis C. C. Costa, Manuel Pedro F. Graca
Summary: Polymeric membranes are commonly used in guided bone regeneration (GBR) in dentistry. The addition of bioactive glasses with therapeutic ions, including zinc, can enhance cell adhesion, proliferation, and differentiation. In this study, bioactive glasses containing different concentrations of zinc were developed, and their structural and biological characteristics were evaluated. The results showed that the zinc-containing bioactive glasses did not exhibit significant antibacterial activity, but the highest concentration of zinc did not compromise bioactivity and promoted cell viability. Cell culture assays using the membranes demonstrated that the addition of zinc improved cell viability and increased alkaline phosphatase production.
Article
Materials Science, Multidisciplinary
Silvia Rodrigues Gavinho, Bruno Miguel Goncalves Melo, Joao Paulo Borges, Jorge Carvalho Silva, Manuel Pedro Fernandes Graca
Summary: Biomaterial coatings on dental implants, particularly using bioglass with therapeutic ions, such as cerium, can improve the integration rate and bond between bone and implant. Cerium oxide addition does not affect the glass structure, but increases the number of non-bridging oxygens. It also enhances the antioxidant and impedance properties of the glass, making it suitable for use as a coating material on dental implants.
Article
Biochemistry & Molecular Biology
Imen Hammami, Silvia Rodrigues Gavinho, Ana Sofia Padua, Maria do Carmo Lanca, Joao Paulo Borges, Jorge Carvalho Silva, Isabel Sa-Nogueira, Suresh Kumar Jakka, Manuel Pedro Fernandes Graca
Summary: In this study, a biomaterial for implant coatings based on 45S5 Bioglass modified with different amounts of niobium pentoxide (Nb2O5) was developed to address the problem of bacterial infection during implant placement. The results showed that the samples loaded with 2 mol% Nb2O5 had the highest bioactivity and greatest antibacterial effect.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Physical
Susana Devesa, Filipa Goncalves, Manuel Graca
Summary: Iron niobate (FeNbO4) was prepared using the sol-gel method via two processes: colloidal gel and polymeric gel. Heat treatments at different temperatures were applied to the obtained powders based on differential thermal analysis. The structure and morphology of the samples were characterized using X-ray diffraction and scanning electron microscopy. Dielectric measurements were conducted in the radiofrequency and microwave range, revealing the influence of the preparation method on structural, morphological, and dielectric properties. The polymeric gel method resulted in the formation of monoclinic and orthorhombic iron niobate at lower temperatures, with noticeable differences in morphology and a relaxation mechanism observed in all samples.
Article
Chemistry, Physical
Joao P. F. Carvalho, Tania Vieira, Jorge Carvalho Silva, Paula I. P. Soares, Nuno M. Ferreira, Carlos O. Amorim, Silvia Soreto Teixeira, Manuel P. F. Graca
Summary: In this study, KFeO2 magnetic nanoparticles were synthesized using a proteic sol-gel method and powdered coconut water as a precursor. Scanning electron microscopy revealed micrometric grains. The samples exhibited saturation magnetizations between 15.5 and 24.1 emu/g at 300 K with an applied field of 50 kOe. Cell compatibility assays showed cytotoxicity only in samples treated at 350 degrees C at concentrations up to 5 mg/mL. However, the samples containing KFeO2 displayed good biocompatibility with low specific absorption rates (1.55-5.76 W/g).
Article
Chemistry, Multidisciplinary
Pedro R. Prezas, Manuel J. Soares, Joao P. Borges, Jorge C. Silva, Filipe J. Oliveira, Manuel Pedro F. Graca
Summary: Conventional methods fail to achieve electrical charging of atmospheric plasma spray (APS) hydroxyapatite (Hap) coatings, but a new non-contact, electrode-free method - corona charging achieves this goal. Charged coatings show higher bioactivity compared to non-charged coatings, promoting osteoblastic cell proliferation and increased intake of calcium and phosphorus. The results of this study indicate the promising potential of corona charging in orthopedics and dental implantology.
Article
Crystallography
Marina Vieira Peixoto, Florinda Mendes Costa, Susana Devesa, Manuel Pedro Fernandes Graca
Summary: BiFeO3 fibers were prepared using the Laser Floating Zone (LFZ) technique at different growth speeds. The samples were characterized structurally and morphologically using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM), and electrically characterized using impedance spectroscopy. XRD patterns confirmed BiFeO3 as the major phase in all samples. Fibers grown at 10 mm/h showed superior structural and morphological properties. Dielectric characterization revealed a thermally activated relaxation phenomenon in all samples, with a higher dielectric constant observed at a growth pull rate speed of 10 mm/h.
Article
Biochemistry & Molecular Biology
Imen Hammami, Silvia Rodrigues Gavinho, Ana Sofia Padua, Isabel Sa-Nogueira, Jorge Carvalho Silva, Joao Paulo Borges, Manuel Almeida Valente, Manuel Pedro Fernandes Graca
Summary: Implantology is important for oral rehabilitation, and this study aimed to address challenges by developing a biomaterial for dental implant coating based on zirconium-modified 45S5 Bioglass. The incorporation of zirconium enhanced conductivity and showed antibacterial effects, without cytotoxicity, making it a potential coating material for dental implants.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Silvia Rodrigues Gavinho, Ana Sofia Padua, Laura Isabel Vilas Holz, Isabel Sa-Nogueira, Jorge Carvalho Silva, Joao Paulo Borges, Manuel Almeida Valente, Manuel Pedro Fernandes Graca
Summary: In this study, Bioglass 45S5 with added SrO or MgO was developed and its physical and biological properties were evaluated. The results showed that the addition of these ions promoted a slight increase in the number of non-bridging oxygens, decreased cell toxicity of Bioglass 45S5, and enhanced antibacterial effect.
Article
Crystallography
Eduardo da Silva Gomes, Antonia Millena de Oliveira Lima, Silvia Rodrigues Gavinho, Manuel Pedro Fernandes Graca, Susana Devesa, Ana Angelica Mathias Macedo
Summary: Bioceramics, in the form of powder, coatings or prostheses, are widely used in medical and dental areas for repairing and replacing parts of the human body. In this study, hydroxyapatite nanocrystalline powders were synthesized and sintered with a blend of galactomannan and chitosan. The influence of the blend content on the bioceramics was investigated, and it was found that increasing the blend percentage led to an increase in grain size and a decrease in density and hardness of the samples.
Article
Crystallography
Eya Rezgui, Najoua Ouerfelli, S. R. Gavinho, J. P. F. Carvalho, M. P. F. Graca, S. Soreto Teixeira
Summary: The compounds (Na1.5Mn3MnIII)-Mn-II (0.5)(AsO4) (3) and Na1.5MnII Fe-3(III) (0.5)(AsO4) (3) were synthesized via a high-temperature solid-state combustion reaction and characterized. X-ray diffraction measurements showed their monoclinic crystal structures. These compounds have potential applications due to their unique structural and electrical properties.
Article
Engineering, Biomedical
Imen Hammami, Silvia Rodrigues Gavinho, Suresh Kumar Jakka, Manuel Almeida Valente, Manuel Pedro Fernandes Graca, Ana Sofia Padua, Jorge Carvalho Silva, Isabel Sa-Nogueira, Joao Paulo Borges
Summary: This study demonstrates the development of antibacterial materials for implant coatings by incorporating copper into 45S5 Bioglass((R)). By combining the regenerative properties of Bioglass((R)) with the antimicrobial effects of copper, this material has the potential to prevent infections, enhance osseointegration, and improve the long-term success of implants.
JOURNAL OF FUNCTIONAL BIOMATERIALS
(2023)
