A5027575478- Anodic Oxide Films and Nanostructures
- Magnetic properties of thin films
- Nanoporous metals and alloys
- Advanced Photocatalysis Techniques
- Semiconductor materials and devices
- Quantum Dots Synthesis And Properties
- Magnetic Properties of Alloys
- Nanowire Synthesis and Applications
- Magnetic and transport properties of perovskites and related materials
- Magnetic Properties and Applications
- Electrodeposition and Electroless Coatings
- ZnO doping and properties
- TiO2 Photocatalysis and Solar Cells
- Iron oxide chemistry and applications
- Transition Metal Oxide Nanomaterials
- Chalcogenide Semiconductor Thin Films
- Microstructure and Mechanical Properties of Steels
- Corrosion Behavior and Inhibition
- Metallic Glasses and Amorphous Alloys
- Gas Sensing Nanomaterials and Sensors
- Nanotechnology research and applications
- Additive Manufacturing and 3D Printing Technologies
- Thermal Expansion and Ionic Conductivity
- Characterization and Applications of Magnetic Nanoparticles
- Material Selection and Properties
Universidade do Porto
2015-2025
INESC TEC
2019
Universidade Sénior Contemporânea
2014
The role of the alumina barrier layer thickness (δb) on growth Ni nanowires (NWs) in porous anodic (PAA) has been revealed. By varying final anodization voltage to form dendrites at bottom nanoporous structure, we are able optimize δb (in 2–16 nm range), allowing us obtain a pore filling percentage (fp) almost 100% for = 10 nm. However, deviations from this optimal δb-value led strong decrease fp. Moreover, an increase electrodeposition efficiency (EE) and NW homogeneity was also verified up...
Investigation of the effect Ti surface roughness on formation, organization, hexagonal arrangement and length TiO<sub>2</sub> NTs.
Iron-based nanoparticles have emerged as promising candidates for diverse biomedical applications, including cell separation, targeted drug delivery, hyperthermia therapy, and magnetic resonance imaging. This study reports the scalable synthesis of high-magnetization iron-based with controlled anisotropic shapes, achieved via a two-step process. Hematite nanoparticles, featuring nanocube, nanoellipse, nanoneedle morphologies, were synthesized through hydrolysis ferric chloride in presence...
In nanoporous alumina, surface pretreatment prior to the anodization process plays a crucial role in nanopore formation, strongly influencing their organization and size uniformity. this work, an effective control of anodic aluminum oxide (AAO) hexagonal order uniformity was achieved by simply changing initial electropolishing time. A drastic change nanoscale topography treated foils observed, intrinsic features were revealed. The effect such distinct landscapes on AAO after first second...
Hematite is getting great attention as an environmentally friendly material for photoelectrochemical water splitting, due to its narrow band gap (1.9–2.2 eV), nontoxicity, low cost, high stability and wide availability. However, hematite shortcomings such absorption coefficient, short hole diffusion length, or poor electrical conductivity lead multiple electron–hole recombinations efficiency losses. This work describes the preparation of nanostructured photoelectrodes by a hydrothermal...
The filling of hierarchical branched porous anodic alumina (PAA) templates with magnetic and metallic nanowires using pulsed electrodeposition is here addressed in detail. We show that the potential (and current) reveals clear anomalies when each generation pores created by steady-state or non-steady-state anodisation completely filled, thus signalising clearly growth stages. This allowed us to infer stage PAA corresponds a new level structure. (current) were related change porosity, linear...
With the increasing demand for high quality methods fast fabrication of extremely aspect ratio nanoparticles, research efficient, low-cost and simple techniques has become fundamental.A promising approach on synthesis these materials is here addressed.Pulsed electrodeposition in porous anodic alumina templates was improved enabling, first time, a cost effective method vertically aligned nanomaterials with ratios never reported this method.Iron nanowires were electrodeposited effect...
The fundamental understanding of the barrier layer (δb) growth in TiO2 nanotubes (NTs) is here established and compared with classical metal oxidation theory from Mott Cabrera. role δb anodization NTs under different applied potentials times was analyzed using scanning transmission electron microscopy (STEM). Contrary to well-known case anodic aluminum oxide, we found that progressively grows over time due nonsteady regime. We then establish a relation between phenomenological voltage,...
Multilayered WO3 nanosquare platelet films were successfully grown on transparent TCO substrates by spray-coating nanoparticles aqueous suspension prepared the sol–gel method. This work assesses influence of two annealing schemes in photoresponse photoelectrodes with different film thicknesses. The photoelectrochemical characterization reveals that slow-heating ramp produces a photoelectrode an improved photocurrent density 1.6 mA cm–2 at 1.23 V vs RHE. Comparing same thickness, yields...
Zero thermal expansion (ZTE) composites are typically designed by combining positive (PTE) with negative (NTE) materials acting as compensators and have many diverse applications, including in high-precision instrumentation biomedical devices. La(Fe1–x,Six)13-based compounds display several remarkable properties, such giant magnetocaloric effect very large NTE at room temperature. Both linked via strong magnetovolume coupling, which leads to sharp magnetic volume changes occurring...
Abstract This study introduces a novel, eco-friendly approach for the extraction and application of Spirulina (Sp.) pigments in alginate bioplastics, representing significant advancement over traditional dyeing methods. The research explores zero waste model process Fab Lab setting, involving three stages, liquid dye preparation, fibre dyeing, bioplastic with focus on utilizing all by-products sustainably. In preparation phase, vibrant blue-green were successfully extracted from powder....
Abstract The article endeavours to establish improved design practices in the development of textile products and explore utilisation sustainable materials future. Through a comprehensive literature review, valuable information data were gathered reflect upon gain essential knowledge about biomaterials. study aims address question what new skills designers need acquire order effectively select these for their projects. Subsequently, by studying characterising various such as biopolymers from...
Magnetic shape memory alloys are under intensive investigation due to their unusual physical properties, such as magnetic effect, field induced superelasticity, direct and inverse magnetocaloric effect etc., promising for novel applications. One of the intriguing properties these materials in a single phase state is giant magnetoresistance. Here we report remarkable results about magnetoresistive epitaxial films Ni52.3Mn26.8Ga20.9 alloy temperature range 100-370 K, well below martensitic...
We investigate equilibrium properties of an exchange-spring magnetic system constituted a soft layer (e.g., Fe) given thickness on top hard FePt). The magnetization profile $M(z)$ as function the atomic position ranging from bottom to is obtained in two cases with regard layer: (i) case rigid interface (the FePt single layer), analytically exact solution sine-Gordon equation Cauchy's boundary conditions. Additional numerical simulations also confirm this result. Asymptotic expressions show...
A complex cyclic TiO<sub>2</sub>-NTs porosity trend throughout anodization was found, due to the microscopic mechanisms behind nanotubes' formation and growth.
Through simulations and experiments, we show that extending vortex state magnetic nanodots into the third dimension boosts gyrotropic frequency up to 5 GHz, compared sub-GHz excitations observed in planar structures.
The application of femtosecond laser interferometry to direct patterning thin-film magnetic alloys is demonstrated. formation stripe gratings with submicron periodicities achieved in Fe1−xVx (x = 18–34 wt. %) layers, a difference moments up Δμ/μ ∼ 20 between adjacent stripes but without any significant development the topographical relief (&lt;1% film thickness). produced exhibit robust effect their anisotropy shape on magnetization curves plane. obtained data witness ultrafast diffusive...
Pulsed electrodeposition prepared porous alumina templates with Ni nanowires pore filling ranged from 1 to 100%, depending on the barrier-layer thickness, were probed by continuous wave ferromagnetic resonance at room temperature. For completely filled samples, a single peak was observed in whole range of angles between applied magnetic field and normal sample plane. Its position described Kittel formula that takes into account shape anisotropy individual wires dipolar interactions them....
Highly ordered TiO2 nanotubes (NTs) were synthesized by the electrochemical anodization of Ti foils subjected to electropolishing (EP) pre-treatment. We found that surface roughness plays an important role in onset pore nucleation enhancing local focusing effect electrical field. Additionally, EP induces formation dimple structures on metal surface, which can work as a pre-pattern prior anodization. These shallow ripples lead preferentially nucleation, offering organizational improvement...
The use of conductive polymers as thin films has become increasingly popular for a vast array applications, such biomedical in the form microelectrodes, energy harvesting, thermal and electrical solutions. In this work, we studied effects different concentrations ratios monomer 3,4-ethylenedioxythiophene (EDOT) to poly(4-styrenesulfonate) (PSS) two distinct modes electrochemical deposition (Potentiodynamic Potentiostatic) polymerize deposit PEDOT:PSS...
We have studied exchange coupled FePt/Fe magnetic layers using the technique of ferromagnetic resonance (FMR). The FePt show strong uniaxial perpendicular anisotropy, growing in L1 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> epitaxial phase on MgO (100). considered case for two thicknesses Fe: 2 nm and 3.5 nm, which exhibit rigid magnet exchange-spring behavior. All are limited to 10 nm. FMR results display multipeaked spectra, where...
Thin polycrystalline Co2FeGe films with composition close to stoichiometry have been fabricated using magnetron co-sputtering technique. Effects of substrate temperature (TS) and post-deposition annealing (Ta) on structure, static dynamic magnetic properties were systematically studied. It is shown that elevated TS promote formation ordered L21 crystal structure. Variation allow modification in a broad range. Saturation magnetization ~920 emu/cm3 low damping parameter α ~ 0.004 achieved for...