Soraya Sangiao - Profile on Academia.edu (original) (raw)

Papers by Soraya Sangiao

Growth of Magnetic Tips by Focused Electron Beam Induced Deposition (FEBID)

Bulletin of the American Physical Society, Mar 18, 2021

arXiv (Cornell University), Sep 27, 2017

In this work, we present a detailed investigation of the magnetic properties of cobalt nanosphere... more In this work, we present a detailed investigation of the magnetic properties of cobalt nanospheres grown on cantilever tips by Focused Electron Beam Induced Deposition (FEBID). The cantilevers are extremely soft and the cobalt nanospheres are optimized for Magnetic Resonance Force Microscopy (MRFM) experiments, which implies that the cobalt nanospheres must be as small as possible while bearing high saturation magnetization. It is found that the cobalt content and the corresponding saturation magnetization of the nanospheres decrease for nanosphere diameters below 300 nm. Electron holography measurements show the formation of a magnetic vortex state in remanence, which nicely agrees with magnetic hysteresis loops performed by local magnetometry showing negligible remanent magnetization. As investigated by local magnetometry, optimal behavior for highresolution MRFM has been found for cobalt nanospheres with diameter of ≈200 nm, which present atomic cobalt content of ≈83 at% and saturation magnetization of 10 6 A/m, around 70% of the bulk value. These results represent the first comprehensive investigation of the magnetic properties of cobalt nanospheres grown by FEBID for application in MRFM.

Characterization of spin current to charge current conversion via ISHE effect by Spin Pumping in YIG/Bi bilayers

Resumen del póster presentado al 10th International Symposium on Metallic Multilayers (MML), cele... more Resumen del póster presentado al 10th International Symposium on Metallic Multilayers (MML), celebrado en Madrid (España) del 17 al 21 de junio de 2019.Spin Pumping technics have been used here in a YIG//Bi bilayer structure to generate a pure spin current flowing within the Bi metallic layer, in order to measure spin to charge conversion parameters. This spin to charge conversion, is observed in the metallic (Bi) layer as a result of the Inverse Spin Hall Effect (ISHE), widely documented in literature. After setting up an external static magnetic field, Ferromagnetic Resonance (FMR) h as been excited within the magnetic layer (YIG) of the samples, using a broadband shorted microstrip RF setup. A pure spin current is obtained in the Bi metallic layer, where Spin Orbit Interaction (SOI) gives rise to a selective scattering, resulting in perpendicular charge current, which has been measured, directly, or via the voltage induced by this current on the sample edges. YIG magnetic insulator layer in place of a conducting one has been chosen to avoid superposition of unwanted electric signals under resonance condition as done in ref [3]. The dependences of the measured ISHE Voltage with frequency, metallic layer thickness, static magnetic field angle and radiofrequency power have been measured and analysed. Results were compared with those obtained in references (where a conducting magnetic layer was used), (where Platinum was used as metallic layer in place of Bismuth) and (where the same bilayer nanostructure YIG//Bi was analysed in a RF monofrequency cavity setup) Finally, the evolution of the ISHE voltage with ageing of the samples has been observed and systematically investigated.Peer reviewe

Physical Review Applied

We present the parametric excitation of spin-wave modes in yttrium iron garnet (YIG) microdisks v... more We present the parametric excitation of spin-wave modes in yttrium iron garnet (YIG) microdisks via parallel pumping. Their spectroscopy is performed using magnetic resonance force microscopy (MRFM), while their spatial profiles are determined by microfocus Brillouin light scattering (BLS). We observe that almost all the fundamental eigenmodes of an in-plane magnetized YIG microdisk, calculated using a micromagnetic eigenmode solver, can be excited using the parallel pumping scheme, as opposed to the transverse one. A comparison between the MRFM and BLS data on the one hand, and the simulations on the other hand, provides the complete spectroscopic labeling of over 40 parametrically excited modes. Our findings could be promising for spin-wave-based computation schemes, in which the amplitudes of a large number of spin-wave modes have to be controlled.

Magnetic resonance and structural properties of high quality yttrium iron garnet (YIG) thin films deposited by a Chemical solution synthesis

Resumen del trabajo presentado al 14th International Workshop on Magnetism & Superconductivity at... more Resumen del trabajo presentado al 14th International Workshop on Magnetism & Superconductivity at the Nanoscale, celebrado en Coma-Ruga, El Vendrell (Espana) del 1 al 6 de julio de 2018.

arXiv (Cornell University), Jan 31, 2023

We present the parametric excitation of spin-wave modes in YIG microdisks via parallel pumping. T... more We present the parametric excitation of spin-wave modes in YIG microdisks via parallel pumping. Their spectroscopy is performed using magnetic resonance force microscopy (MRFM), while their spatial profiles are determined by micro-focus Brillouin light scattering (BLS). We observe that almost all the fundamental eigenmodes of an in-plane magnetized YIG microdisk, calculated using a micromagnetic eigenmode solver, can be excited using the parallel pumping scheme, as opposed to the transverse one. The comparison between the MRFM and BLS data on one side, and the simulations on the other side, provides the complete spectroscopic labeling of over 40 parametrically excited modes. Our findings could be promising for spin-wave-based computation schemes, in which the amplitudes of a large number of spin-wave modes have to be controlled.

Bulletin of the American Physical Society, Mar 15, 2016

Given the high interest in the fabrication and application of carbon-based materials, we present ... more Given the high interest in the fabrication and application of carbon-based materials, we present a new and cost-effective method for the synthesis of graphite oxide nanoplatelets (GONP) using bamboo pyroligneous acid (BPA) as source. GONP-BPA present lateral dimensions of 5-100 micro-meter and thickness less than 80 nm, as confirmed by TEM. EEL spectra show that locally the carbon is mainly in sp 2 bonding configuration and confirm a short/medium range crystalline order. Elemental analysis by EDX confirms the presence of oxygen in an atomic percentage ranging from 17 to 5%. For electrical characterization, single platelets were contacted by focused-ion-beam-induced deposition of Pt nanowires. The four-point probe electrical conductivity shows a direct correlation with the oxygen percentage. Three orders of magnitude conductivity rise is observed by the oxygen reduction, reaching a value of 2.3x10 3 S/m at the final deoxidation degree. The results suggest that GONP-BPA could be used in the development of advanced devices and sensors.

Nanoscale advances, 2021

Emergent technologies are required in the field of nanoelectronics for improved contacts and inte... more Emergent technologies are required in the field of nanoelectronics for improved contacts and interconnects at nano and micro-scale. In this work, we report a highly-efficient nanolithography process for the growth of cobalt nanostructures requiring an ultra-low charge dose (15 mC cm À2 , unprecedented in single-step charge-based nanopatterning). This resist-free process consists in the condensation of a $28 nm-thick Co 2 (CO) 8 layer on a substrate held at À100 C, its irradiation with a Ga + focused ion beam, and substrate heating up to room temperature. The resulting cobalt-based deposits exhibit sub-100 nm lateral resolution, display metallic behaviour (room-temperature resistivity of 200 mU cm), present ferromagnetic properties (magnetization at room temperature of 400 emu cm À3) and can be grown in large areas. To put these results in perspective, similar properties can be achieved by room-temperature focused ion beam induced deposition and the same precursor only if a 2 Â 10 3 times higher charge dose is used. We demonstrate the application of such an ultra-fast growth process to directly create electrical contacts onto graphene ribbons, opening the route for a broad application of this technology to any 2D material. In addition, the application of these cryo-deposits for hard masking is demonstrated, confirming its structural functionality.

Nanotechnology, Jan 16, 2016

We demonstrate that the spectral location of extraordinary optical transmission (EOT) resonances ... more We demonstrate that the spectral location of extraordinary optical transmission (EOT) resonances in metallic arrays of rectangular holes can be plasmonically tuned in the near and mid-infrared ranges. The experiments have been performed on patterned gold films. We focus on a subset of localized resonances occurring close to the cut-off wavelength of the holes, λ c. Metals are usually regarded as perfect electric conductors in the infrared regime, with an EOT cut-off resonance found around λ c = 2 L for rectangular holes (L being the long edge). For real metals, the penetration of the electromagnetic fields is simply seen as effectively enlarging L. However, by changing the hole short edge, we have found that λ c varies due to the excitation of gap surface plasmon polaritons. Finite-element calculations confirm that in these high aspect ratio rectangles with short edges two important aspects have to be taken into account in order to explain the experiments: the finite conductivity of...

Materials

Focused Ion Beam patterning has become a widely applied technique in the last few decades in the ... more Focused Ion Beam patterning has become a widely applied technique in the last few decades in the micro- and nanofabrication of quantum materials, representing an important advantage in terms of resolution and versatility. However, ion irradiation can trigger undesired effects on the target material, most of them related to the damage created by the impinging ions that can severely affect the crystallinity of the sample, compromising the application of Focused Ion Beam to the fabrication of micro- and nanosized systems. We focus here on the case of Bi2Se3, a topological material whose unique properties rely on its crystallinity. In order to study the effects of ion irradiation on the structure of Bi2Se3, we irradiated with Ga+ ions the full width of Hall-bar devices made from thin films of this material, with the purpose of inducing changes in the electrical resistance and characterizing the damage created during the process. The results indicate that a relatively high ion dose is ne...

Nanoscale Advances

NanoSQUIDs are quantum sensors that excel in detecting a change in magnetic flux with high sensit... more NanoSQUIDs are quantum sensors that excel in detecting a change in magnetic flux with high sensitivity and high spatial resolution. Here, we employ Ga+ focused ion beam induced deposition techniques to grow W–C nanoSQUIDs and we investigate their electrical response.

Open Research Europe

Background: The use of a focused ion beam to decompose a precursor gas and produce a metallic dep... more Background: The use of a focused ion beam to decompose a precursor gas and produce a metallic deposit is a widespread nanolithographic technique named focused ion beam induced deposition (FIBID). However, such an approach is unsuitable if the sample under study is sensitive to the somewhat aggressive exposure to the ion beam, which induces the effects of surface amorphization, local milling, and ion implantation, among others. An alternative strategy is that of focused electron beam induced deposition (FEBID), which makes use of a focused electron beam instead, and in general yields deposits with much lower metallic content than their FIBID counterparts. Methods: In this work, we optimize the deposition of tungsten-carbon (W-C) nanowires by FEBID to be used as electrical contacts by assessing the impact of the deposition parameters during growth, evaluating their chemical composition, and investigating their electrical response. Results: Under the optimized irradiation conditions, t...

Superconducting W-C nanopillars fabricated by Ga+ focused ion beam induced deposition

Journal of Solid State Chemistry

ACS Applied Materials & Interfaces

Metallic nanopatterns are ubiquitous in applications that exploit the electrical conduction at th... more Metallic nanopatterns are ubiquitous in applications that exploit the electrical conduction at the nanoscale, including interconnects, electrical nanocontacts, and small gaps between metallic pads. These metallic nanopatterns can be designed to show additional physical properties (optical transparency, plasmonic effects, ferromagnetism, superconductivity, heat evacuation, etc.). For these reasons, an intense search for novel lithography methods using uncomplicated processes represents a key ongoing issue in the achievement of metallic nanopatterns with high resolution and high throughput. In this contribution, we introduce a simple methodology for the efficient decomposition of Pd 3 (OAc) 6 spin-coated thin films by means of a focused Ga + beam, which results in metallic-enriched Pd nanostructures. Remarkably, the usage of a charge dose as low as 30 μC/cm 2 is sufficient to fabricate structures with a metallic Pd content above 50% (at.) exhibiting low electrical resistivity (70 μΩ• cm). Binary-collision-approximation simulations provide theoretical support to this experimental finding. Such notable behavior is used to provide three proof-of-concept applications: (i) creation of electrical contacts to nanowires, (ii) fabrication of small (40 nm) gaps between large metallic contact pads, and (iii) fabrication of large-area metallic meshes. The impact across several fields of the direct decomposition of spin-coated organometallic films by focused ion beams is discussed.

Nanomaterials

Since its discovery in 1911, superconductivity has represented an equally inciting and fascinatin... more Since its discovery in 1911, superconductivity has represented an equally inciting and fascinating field of study in several areas of physics and materials science, ranging from its most fundamental theoretical understanding, to its practical application in different areas of engineering. The fabrication of superconducting materials can be downsized to the nanoscale by means of Focused Ion/Electron Beam Induced Deposition: nanopatterning techniques that make use of a focused beam of ions or electrons to decompose a gaseous precursor in a single step. Overcoming the need to use a resist, these approaches allow for targeted, highly-flexible nanopatterning of nanostructures with lateral resolution in the range of 10 nm to 30 nm. In this review, the fundamentals of these nanofabrication techniques are presented, followed by a literature revision on the published work that makes use of them to grow superconducting materials, the most remarkable of which are based on tungsten, niobium, mo...

HOA-14 Dynamic instabilitiy in high power FMR of BiYIG nanodisks

One current goal of spintronics is the development of sustainable information technology based on... more One current goal of spintronics is the development of sustainable information technology based on pure spin currents. One promising way to do this is to use spin waves (SWs) in low damping insulating ferrimagnets like yttrium iron garnet (YIG) where relaxation can be controlled by spin orbit torque (SOT) at a heavy metal interface [1]. However, such metal/insulator hybrid devices exhibit saturation of SW amplification due to nonlinear coupling between modes [2].<br/>Two strategies can be considered to overcome these issues. i) Nanopatterning leads to quantization of SW modes [3], thereby limiting the available nonlinear processes [4]. ii) Tuning the perpendicular magnetic anisotropy (PMA) can be used to control the sign of the nonlinear frequency shift [5]. Recently, the growth of ultra-thin films of bismuth doped YIG (BiYIG) with tunable PMA has been achieved [6], resulting in greatly improved characteristics of SOT emitted SWs [7].<br/>Here, we study the magnetization ...

5C-1 - Ultrafast growth of metallic deposits by focused ion beam irradiation under cryogenic conditions (Cryo-FIBID)

Here, we will show the application of Cryo-FIBID to other precursors beyond W(CO)6, with the aim ... more Here, we will show the application of Cryo-FIBID to other precursors beyond W(CO)6, with the aim of obtaining ultrafast growth of metallic deposits, and eventually additional functional properties. In particular, we will discuss the results obtained using the (CH3)3Pt(CpCH3) precursor, which is commonly found in commercial FIB equipment.

Cornell University - arXiv, Mar 10, 2022

NanoSQUIDs are quantum sensors that excel in detecting a small change in magnetic flux with high ... more NanoSQUIDs are quantum sensors that excel in detecting a small change in magnetic flux with high sensitivity and high spatial resolution. Here, we employ resist-free direct-write Ga + Focused Ion Beam Induced Deposition (FIBID) techniques to grow W-C nanoSQUIDs, and we investigate their electrical response to changes in the magnetic flux. Remarkably, FIBID allows the fast (3 min) growth of 700 nm×300 nm Dayem-bridge nanoSQUIDs based on narrow nanowires (50 nm wide) that act as Josephson junctions. The observed transfer coefficient (output voltage to magnetic flux change) is very high (up to 1301 µ V/Φ0), which correlates with the high resistivity of W-C in the normal state. We discuss here the potential of this approach to reduce the active area of the nanoSQUIDs to gain spatial resolution as well as their integration on cantilevers for scanning-SQUID applications.

Low-resistivity Pd nanopatterns created by a direct electron beam irradiation process free of post-treatment steps

Nanotechnology, 2022

The ability to create metallic patterned nanostructures with excellent control of size, shape and... more The ability to create metallic patterned nanostructures with excellent control of size, shape and spatial orientation is of utmost importance in the construction of next-generation electronic and optical devices as well as in other applications such as (bio)sensors, reactive surfaces for catalysis, etc. Moreover, development of simple, rapid and low-cost fabrication processes of metallic patterned nanostructures is a challenging issue for the incorporation of such devices in real market applications. In this contribution, a direct-write method that results in highly conducting palladium-based nanopatterned structures without the need of applying subsequent curing processes is presented. Spin-coated films of palladium acetate were irradiated with an electron beam to produce palladium nanodeposits (PdNDs) with controlled size, shape and height. The use of different electron doses was investigated and its influence on the PdNDs features determined, namely: (1) thickness of the deposits...