J. Briones

• PhD in Physics from Université Henri Poincaré
• Professor (Full) at Consejo Nacional de Ciencia y Tecnología

The multi-resonant response of three-steps tapered dipole nano-antennas, coupled to a resistive and fast micro-bolometer, is investigated for the efficient sensing in the infrared band. The proposed devices are designed to operate at 10.6 μm, regime where the complex refractive index of metals becomes important, in contrast to the visible counterpa...

In this letter, the authors develop an optimized Seebeck nanoantenna design suitable for IR harvesting applications. The design is optimized via the so-called particle-swarm-optimization algorithm (PSO), an evolutionary algorithm able to drive the morphology of a nano-object towards an optimum. Along with the so-called nanoloading technique, effort...

Inspired in the extraordinary ability of metallic resonant nano-cavities to transmit light towards a substrate beneath them, the authors introduce a quite simple design of nano- cavities displaying enhanced anti-reflective properties in the UV-vis band. With the aid of an evolutionary algorithm, which is based on social rules, the authors drive the...

Due to strong inter-band transitions, the optical response of copper exhibits a high light absorbance in the visible region of the spectrum, recovering blue wavelengths and reflecting a reddish color. In this contribution, copper is split into subwavelength thin films, which are separated by silicon dioxide dielectric layers to take advantage of ph...

Minor pilins are the first type IV pili (T4P) proteins known to interact with electroactive surfaces, acting as an anode in electron transfer. In this study, we used the mechanically controlled break-junction (MCBJ) technique to measure the electrical conductance in bulk solution of the minor pilin PilV from the acidophile Acidithiobacillus thiooxi...

Multilayer (ML) thin films are an optical engineering strategy to address reflectivity losses in GaAs photovoltaic devices, enhancing the power conversion of light around a single wavelength. Inspired by the enhanced response of periodic ML Bragg mirrors, the authors introduce quite simple antireflective designs based on two periods and single peri...

Since regenerative medicine is highly dynamic and it is under continuous evolution, one of the challenge points to the development of new materials is the potential to mimic the extracellular matrix (ECM) and biocompatibility within living organisms. The main objective of this study is the development of polymeric fibers based on mixtures of Polyla...

Superparamagnetic magnetite Fe3O4 nanoparticles (NPs) were synthesized by the coprecipitation method and stabilized with meso-2,3-dimercaptosuccinic acid (DMSA) under ambient conditions and a nitrogen atmosphere at room temperature in one simple step. The X-ray diffraction (XRD) analysis of Fe3O4 NPs confirmed their cubic spinel structure with high...

To design a phosphor for near ultraviolet (n-UV) based white light emitting diodes (wLED) with low correlated color temperature (CCT) and high CRI, a series of highly Eu³⁺ activated tellurite samples was prepared. Glass ceramic (GC) containing Eu2Te6O15 microcrystals were obtained as a function of crystallization time from 0 to 4h at 435 °C. X-ray...

The authors demonstrate both experimentally and numerically the high tunability that can be achieved in the optical response of sputtered multilayered metal-dielectric thin films. The wavelength dependence of both the transmission and reflectance is analyzed in terms of the geometrical parameters of transparent heterostructures consisting of altern...

The authors investigate the efficiency of a series of broadband rectennas designed to harvest the free-propagating electromagnetic energy at terahertz frequencies. We analyze by simulations the case of self-complementary square- and Archimedean-spiral antennas coupled to L-shaped self-switching diodes (L-SSDs). First, the geometry (i.e., the width...

In this letter, we evaluate the conversion efficiency of thermally isolated Seebeck nanoantennas by numerical simulations and discuss their uses and scope for energy harvesting applications. This analysis includes the simple case of titanium-nickel dipoles suspended in air above the substrate by a 200 nm silicon dioxide membrane to isolate the heat...

In this work, the influence of the surface depletion layer on the formation of a two-dimensional electron gas in AlGaAs/GaAs modulated dopedheterostructures is studied. The authors explore a method for estimating the depletion region inside of the GaAs-based heterostructures by using the longitudinal optical and L- amplitude modes observed in Raman...

In order to improve the rectification efficiency and current–voltage characteristics of self-switching diodes (SSD) the DC response is analyzed using technology computer aided design (TCAD). It is demonstrated that by varying geometrical parameters of L- and V-shaped SSDs or changing the dielectric permittivity of the trenches, a near zero threshol...

In this letter, self-switching nanochannels have been proposed as an enabling technology for energy gathering in the terahertz (THz) regime. Such devices combine their diode-like behavior and high-speed of operation in order to generate DC electrical power from high-frequency signals. By using finite-element simulations, we have improved the sensit...

In this letter we introduce a new type of infrared sensor, based on thermocouple nanoantennas, which enables the energy detection and gathering in the mid-infrared region. The proposed detector combines the Seebeck effect, as a transduction mechanism, with the functionalities of the optical antennas for optical sensing. By using finite-element nume...

It is shown that there are many stable configurations for a domain wall pinned by a notch along a magnetic stripe. The stability of several of these configurations is investigated numerically as a function of the thickness of the magnetic film. The depinning mechanism depends on the structure of the domain wall and on the thickness of the magnetic...

The magnetic properties of ordered nanoscale Co/Cu/Py multilayer antidot films with different pore sizes prepared on top of nanoporous alumina membranes are presented. By using Co and Py films separated by a Cu thin layer, and tuning the pore diameters of the NAMs we were able to play with the coercivity of the films and observe stepped magnetizati...

Arrays of metallic thermocouples in the shape of spiral nanoantennas are proposed as infrared detectors, which use the thermoelectric properties of the metallic interfaces to generate electrical DC signals. The responsivity of these types of antennas is evaluated from both theoretical and numerical perspectives pointing out its potential as infrare...

We propose a mid-infrared device based on thermocouple optical antennas for light sensing and energy harvesting applications. We numerically demonstrate that antennas are able to generate low-power dc signals by beneficing of the thermoelectric properties of the metals that constitute them. We theoretically evaluate the optical-to-electrical conver...

Magnetic properties of Co antidot arrays with different hole sizes fabricated by a template-assisted method have been studied by means of first-order reversal curves (FORCs) and micromagnetic simulations. Hysteresis curves show a significant increase of the coercivity of the antidot arrays, as compared with their parent continuous film, which depen...

Thermo-electrical nanoantennas have been proposed as an alternative option for conversion solar energy harvesting applications. In this work, the response of a spiral broadband antenna has been obtained from numerical and theoretical simulations perspectives. The results show that this device exhibits a responsivity of 20mV/W under 117W/cm2, for a...

Cox Ni1−x alloy nanowires with varying Co content (0 ≤ x ≤ 1), having a diameter of 50 nm and a length of 3 μm, have been fabricated by electrodeposition using an anodized aluminum oxide template. The composition and crystalline structure of the CoNi nanowires were determined by high-resolution scanning electron microscopy and energy-dispersive spe...

We report on a method to fabricate laterally modulated Co films using the artificially induced nano-wrinkled surface of a polydimethylsiloxane polymeric film as template. Large area patterning of self-organized parallel wrinkles is formed displaying a submicrometer wavelength. The subsequent deposition of a Co layer on this wavy surface yields a un...

We study the thermally induced depinning process of a single magnetic domain wall (DW) under applied field when the DW is trapped by a notch made in a nanowire shaped from a spin-valve multilayer with in-plane magnetization. In such devices depinning is typically a stochastic process and the depinning field distribution exhibits complex features. B...

Topological modulation of magnetic thin films can induce a magnetic anisotropy of magnetostatic origin. In this paper, we report on the magnetic properties of NiFe layers deposited on wavy Si substrates. Without modulation, the film posses an intrinsic anisotropy. We unambiguously show that patterning the substrate overcomes the intrinsic anisotrop...

A topological modulation of magnetic thin films can induce a magnetic anisotropy of magnetostatic origin. In this letter, we report on the magnetic properties of NiFe layers deposited on wavy shaped Si substrates. Without any modulation, our films always present an intrinsic anisotropy. We show unambiguously that patterning the substrate can overco...

A study on the induction of a magnetic anisotropy of magnetostatic origin in a magnetic thin layer (Ni81Fe19) having a modulated topology was carried out by performing magneto-transport measurements (AMR). Modulation in the nanometric scale is obtained with a new approach based on the electronic lithography. The presence of a uniaxial anisotropy al...

Une étude de l'induction d'une anisotropie magnétique d'origine magnétostatique dans une couche mince magnétique (Ni81Fe19) à topologie modulée a été effectuée grâce aux observations réalisées à l'aide de mesures de magnéto-transport (AMR). La modulation à l'échelle nanométrique est obtenue avec une nouvelle approche basée sur la lithographie élect...

High spatial resolution x-ray photoemission electron microscopy technique has been used to study the influence of the dipolar coupling taking place between the NiFe and the Co ferromagnetic electrodes of micron sized, elliptical shaped magnetic tunnel junctions. The chemical selectivity of this technique allows us to observe independently the magne...

The propagation of a domain wall in a submicron ferromagnetic spin-valve stripe is investigated using giant magnetoresistance. A notch in the stripe efficiently traps an injected wall stopping the domain propagation. The authors show that the magnetic field at which the wall is depinned displays a stochastic nature. Moreover, the depinning statisti...

The propagation of a domain wall in a submicron ferromagnetic spin-valve stripe is investigated using giant magnetoresistance. A notch in the stripe efficiently traps an injected wall stopping the domain propagation. The authors show that the magnetic field at which the wall is depinned displays a stochastic nature. Moreover, the depinning statisti...

Une étude de l'induction d'une anisotropie magnétique d'origine magnétostatique dans une couche mince magnétique (Ni81Fe19) à topologie modulée a été effectuée grâce aux observations réalisées à l'aide de mesures de magnéto-transport (AMR). La modulation à l'échelle nanométrique est obtenue avec une nouvelle approche basée sur la lithographie élect...