Marco Truccato

Università degli Studi di Torino | UNITO · Department of Physics

The investigation of secondary effects induced by ionizing radiation represents a new and ever-growing research field in radiobiology. This new paradigm cannot be investigated only using standard instrumentation and methodologies, but rather requires novel technologies to achieve significant progress. In this framework, we developed diamond-based s...

We have performed ultrasonic liquid phase exfoliation (LPE) of MgB2 in ethanol and investigated the resulting nano-assemblies as a function of the ultrasound processing time. Transmission electron microscopy (TEM) morphological and structural characterization showed that the exfoliated grains have mainly a 2D character and produce Moiré patterns co...

Pristine high-density bulk disks of MgB2 with added hexagonal BN (10 wt.%) were prepared using spark plasma sintering. The BN-added samples are machinable by chipping them into desired geometries. Complex shapes of different sizes can also be obtained by the 3D printing of polylactic acid filaments embedded with MgB2 powder particles (10 wt.%). Our...

We investigate the possibility to directly write electrically conducting channels in the desired position in rutile TiO2 devices equipped with asymmetric electrodes - like in memristive devices - by means of the X-ray nanopatterning technique (XNP, i.e. intense, localized irradiation exploiting an X-ray nanobeam). Device characterization is carried...

We report for the first time on the antimicrobial activity of MgB2 powders produced via the Reactive Liquid Infiltration (RLI) process. Samples with MgB2 wt.% ranging from 2% to 99% were obtained and characterized, observing different levels of grain aggregation and of impurity phases. Their antimicrobial activity was tested against Staphylococcus...

We have investigated the modifications induced in high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi-2212) single crystals by irradiation with an X-ray nanobeam 250 × 250 nm² in size with E = 14.85 keV and a time-averaged photon flux Φ0 = 7.53 × 10⁸ ph s–1. Crystals were mounted onto amorphous substrates with electrical contacts to allow for both X-ray dif...

Three commercial powders of MgB2 were tested in vitro by MTS and LDH cytotoxicity tests on the HS27 dermal cell line. Depending on powders, the toxicity concentrations were established in the range of 8.3–33.2 µg/ml. The powder with the lowest toxicity limit was embedded into polyvinylpyrrolidone (PVP), a biocompatible and biodegradable polymer, fo...

Commercial nanopowders of MgB2 were characterized from the viewpoint of granulometric distribution, structure, microstructure, and pH behavior in water. The powders are very different: a higher amount of the MgB2 phase with a lower tendency for agglomeration determines a higher rate of pH-increase. A higher rate of pH-increase usually produces a st...

X-ray synchrotron sources, possessing high power density, nanometric spot size and short pulse duration, are extending their application frontiers up to the exploration of direct matter modification. In this field, the use of atomistic and continuum models is now becoming fundamental in the simulation of the photoinduced excitation states and event...

We measured the radiation tolerance of commercially available diamonds grown by the Chemical Vapor Deposition process by measuring the charge created by a 120 GeV hadron beam in a 50 μm pitch strip detector fabricated on each diamond sample before and after irradiation. We irradiated one group of samples with 70 MeV protons, a second group of sampl...

The employment of ionizing radiation is a powerful tool in cancer therapy but beyond targeted effects, many studies have highlighted the relevance of its off-target consequences. An exhaustive understanding of the mechanisms underlying these effects is still missing and no real-time data about signals released by cells during irradiation are presen...

Chemical Vapour Deposition (CVD) diamond is being considered as a material for particle detectors in a harsh radiation environment. This article presents beam test results of 3D pixel detectors fabricated with poly-crystalline CVD diamonds. The cells of the devices had a size of 50 µm×50 µm with columns 2.6 µm in diameter. The cells were ganged in...

It is well known that intense synchrotron beams can alter the state of materials, but this effect is generally considered undesired radiation damage. The effect of local irradiation of TiO2 rutile single crystals is investigated by a 56 × 57 nm² synchrotron X‐ray nanobeam at 17.4 keV. Aside from a transient increase of conductivity due to a photovo...

We report on a combined experimental and modelling approach towards the design and fabrication of efficient bulk shields for low-frequency magnetic fields. To this aim, MgB 2 is a promising material when its growing technique allows the fabrication of suitably shaped products and a realistic numerical modelling can be exploited to guide the shield...

We have investigated the modifications induced in the high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi-2212) by X-ray nanopatterning, which is an innovative, photoresist-free, direct-writing approach recently used to fabricate proof-of-concept electrical devices [Truccato et al., Nano Lett. 2016, 16, 1669]. By means of combined synchrotron microdiffracti...

We investigate the microscopic mechanism responsible for the change of macroscopic electrical properties of the Bi2Sr2CaCu2O8+δ high-temperature superconductor induced by intense synchrotron hard x-ray beams. The possible effects of secondary electrons on the oxygen content via the knock-on interaction are studied by Monte Carlo simulations. The ch...

X-ray nanofabrication has so far been usually limited to mask methods involving photoresist impression and subsequent etching. Herein we show that an innovative maskless X-ray nanopatterning approach allows writing electrical devices with nanometer feature size. In particular we fabricated a Josephson device on a Bi2Sr2CaCu2O8+δ (Bi-2212) supercond...

Superstripes 2017 Quantum in Complex Matter: Superconductivity, Magnetism & Ferroelectricity Papers presented at the international conference Superstripes 2017 Ischia Italy June 4-10, 2017 Organized by Non profit organization for scientific research Superstripes onlus Rome International Center for Materials Science Superstripes - RICMASS Chairman...

This paper compares the shielding properties of superconducting (SC) and superimposed superconducting/ferromagnetic (SC/FM) systems, consisting of cylindrical cups with an aspect ratio of height/radius close to unity. Both bilayer structures, with the SC cup placed inside the FM one, and multilayer structures, made up of two SC and two FM alternati...

High- T c superconducting cuprates (HTSC) such as YBa 2 Cu 3 O 7 − x (YBCO) are promising candidates for solid-state THz applications based on stacks of intrinsic Josephson junctions (IJJs) with atomic thickness. In view of future exploitation of IJJs, high-quality superconducting YBCO tape-like single crystals (whiskers) have been synthesized from...

Bi2Sr2CaCu2O8+δ (Bi-2212) superconducting whiskers, owing to their microscopic size, are good candidates for the fabrication of miniaturized devices for production/sensing of THz-radiation based on their Intrinsic Josephson Junctions (IJJ) properties. With this respect, several studies demonstrated the possibility of controlling whisker IJJ paramet...

0.5((1-x)Bi0.8La0.1Pr0.2FeO3 (BLPFO)-xPb(Zr0.52Ti0.48)O3 (PZT))-0.5Polyvinylidene difluoride (PVDF) composite films with x variations 0.25, 0.40 and 0.50 were synthesized using two step mixing, followed by hot pressing. The structural, microstructural, dielectric, magnetic, ferroelectric and magnetodielectric properties of composite films have been...

In this work, we present a study on the interlayer tunneling spectroscopy (ITS) of mixed-phase BiSrCaCuO (BSCCO) superconducting whiskers. The tunneling experiments were carried out on the artificial cross-whisker (twist angle of 90°) junctions. A multiple superconducting energy gap in the cross-whisker junctions was observed, which is attributed t...

In this paper we investigate and compare the shielding properties of superconducting and hybrid superconducting/ferromagnetic systems, consisting of cylindrical cups with an aspect ratio of height/radius close to unity. First, we reproduced, by finite-element calculations, the induction magnetic field values measured along the symmetry axis in a su...

REFERENCES In the microelectronics rush towards smaller and faster circuits, the idea of establishing photolithographic processes based on X-rays to take advantage of their very small wavelength (λ ≲ 1 nm) has already been explored, but the problems related to the fabrication of masks with the necessary contrast and small sizes have discouraged fur...

Al(+3)-doped (Y,Ca)Ba2Cu3O7-y (YBCO) whiskers have been synthesized using a solid-state reaction technique. These materials are promising candidates for solid-state THz applications based on sequences of Josephson Junctions (IJJs). Alumina addition was systematically varied and the effect of aluminium incorporation on the structure has been investi...

We describe the controlled use of a 17 keV X-ray synchrotron nano-beam to progressively change the oxygen doping level in Bi-2212 superconducting whisker-like single crystals. Our data combine structural and electrical information collected on the same crystals, showing a maximum change in the critical temperature Tc of 1.3 K and a maximum elongati...

We synthesized Al doped Y(Ca)Ba2Cu3O7−y (YBCO) whiskers via the solid state reaction method. Al doping was systematically varied in the nominal cationic stoichiometry of YBa2Cu3CaTe0.5AlxO7−y, with 0 ⩽ x ⩽ 0.5. The amount of the grown whiskers increases for nominal Al addition up to x = 0.05, decreasing for larger concentrations. The concentration...

We managed to synthesize non-linear YBa2Cu3Ox whiskers, i.e. half loops or kinked shapes, which are promising candidates for solid-state devices based on the intrinsic Josephson effect and with improved electrical connections. We report on a complete characterization of their structural properties via synchrotron nanoprobe as well as laboratory sin...

We report on combined photoconductivity and annealing experiments in whisker-like crystals of the Bi-Sr-Ca-Cu-O (BSCCO) high-T-c superconductor. Both single-phase Bi2Sr2CaCu2O8+delta (Bi-2212) samples and crystals of the mixed phases Bi2Sr2Ca2Cu3O10+x (Bi-2223)/Bi-2212 have been subjected to annealing treatments at 90 degrees C in air in a few hour...

Unconventional in situ synthesis of MgB2 undoped and doped with fullerene (C-60) was performed by using a single-mode microwave (MW) furnace. Structural properties suggested that C substitutes for B in the crystal lattice of MgB2, while the J(c) showed typical enhancement at high magnetic fields when C chemical doping occurred. This behavior was si...

High-temperature superconducting objects of Bi2Sr2CaCu2O8 and Y Ba2Cu3O7 highly curved in the ab-plane, such as curved/kinked whiskers, bows and ring-like structures, were obtained within a solid–liquid–solid (SLS) grass-like growth mechanism. As-grown objects are crystals with three-dimensional epitaxy similar to conventional single crystals: they...

We describe a method to produce MgB2 bulk via a microwave processing, which has not been reported yet for this material. We used two experimental arrangements, which were different in the form of the graphite thermal activator responsible for the microwave absorption. The reaction products have been analyzed from the morphological, structural and e...

Magnetic shielding properties of MgB2 bulk samples synthesized by the SPS (Spark–Plasma–Sintering) technique were characterized in low applied magnetic fields at temperatures ranging from 20 to 37 K. The used growth technique allows one to produce this compound in different shapes and sizes required for shielding applications. In this framework, sh...

In the past few years, strong efforts have been devoted to improving the frequency of optical-fiber communications. In particular, the use of a special kind of integrated optoelectronic device called an electroabsorption modulated laser (EML) allows communication at 10 Gb s(-1) or higher over long propagation spans (up to 80 km). Such devices are r...

Experimental data show that the normal state resistivity of superconducting Bi2Sr2CaCu2O8 + ? (Bi-2212) whiskers increases after a 6?h irradiation by a synchrotron ?-beam with 17?keV photons. We analyse this result on the basis of previously reported effects in Bi-2212 whiskers due to ageing or heating processes. A finite element model of the expe...

Nowadays Multi-Quantum Well (MQW) structures based on quaternary III-V semiconductor alloys are widely used in optical communication systems. Advanced optoelectronic devices often require the integration of two different functions in the same chip: excellent results in the development of monolithic integration have been reached with the Selective A...

Advanced optoelectronic devices require monolithic integration of different functions at chip level. This is the case of multi-quantum well (MQW) electroabsorption modulated lasers (EMLs) realized by using the selective area growth (SAG) technique, and which can be employed in long-distance, highfrequency optical fiber communication applications. W...

Direct evidence is reported of structural and electronic effects induced on a single Bi(2)Sr(2)CaCu(2)O(8+delta) (Bi-2212) whisker during a progressive annealing process. The crystal was investigated by micro X-ray diffraction (micro-XRD), micro X-ray fluorescence and electrical characterization at the European Synchrotron Radiation Facility, durin...

Direct evidence of oxygen doping control in single phase Bi2Sr2CaCu2O8+δ (Bi-2212) whiskers is reported, along with the changes in their structural properties obtained by varying the growth temperature of the synthesis process in the range from 843 to 872 °C. The as-grown whiskers were investigated by means of x-ray powder diffraction (XRPD), elect...

We report the results of a detailed geometrical and electrical study which has been performed on a YBa2Cu3O7−δ superconducting whisker. This sample has undergone three subsequent steps of micro-machining by means of a focused ion beam (FIB) instrument, in order to progressively decrease its cross-sectional area from ~77 to ~4 µm2, over a length of...

We report new evidences for the thermodynamic instability of whisker crystals in the Bi–Sr–Ca–Cu–O (BSCCO) system. Annealing treatments at 90°C have been performed on two sets of samples, which were monitored by means of X-Rays Diffraction (XRD) and Atomic Force Microscopy (AFM) measurements, respectively. Two main crystalline domains of Bi2Sr2CuCa...

The effect of different Na doping levels on structural and electric transport properties M_gB₂ of bulk samples was investigated. The samples were synthesized by an assisted microwave method using the microwave radiation to heat the powder precursors (Mg and B, high purity) constrained in a stainless steel box. It was found that...

In the present paper we report the results of photoconductivity experiments carried out in nearly optimally doped, single-phase Bi2Sr2CaCu2O8+x (Bi-2212) whiskers. Samples with both straight and bent shapes have been investigated by means of the four-probe and two-probe configurations in dark and in illuminated conditions. Experimental data invaria...

We report a set of resistivity measurements along the a-axis of a Bi2Sr2CaCu2O8+δ microscopic superconducting whisker. The effect of the storage environment on sample ageing has been studied, considering both an air atmosphere at 273 K and a helium atmosphere at about 300 K for an overall storage time of about 100 days. It is clearly shown that the...

We report the observation of a phase transformation which can occur in a microscopic double phase BSCCO whisker at room temperature. We performed electrical resistivity measurements by thermally cycling the whisker in the range 78?300?K in a helium atmosphere and observed a decrease of the Bi-2223 phase amount in favour of the Bi-2212 phase, accomp...

We report the measurement of the a-axis fluctuation conductivity in zero field for Bi2Sr2CaCu2O8+x microcrystals. A complete geometrical characterization allows us to determine the absolute value of the excess conductivity and its temperature behaviour with high accuracy. A careful application of the complete fluctuation theory (Varlamov et al 1999...

We have studied Bi-2212 microcrystals aged at ambient conditions for 40 days. Combined x-ray absorption near edge structure and x-ray fluorescence measurements with micrometer space resolution show both an increase of Cu ⁺ with respect to Cu ²⁺ and an enrichment in Cu vs Bi and Sr cation content near the sample edges in the b...

We report the measurement of the a-axis fluctuation conductivity in zero field for Bi2Sr2CaCu2O8+x microcrystals. A good geometrical characterization and an original method for data analysis allow to determine its temperature behaviour to a high accuracy. The correct application of the complete fluctuation theory [A. A. Varlamov et al., Adv. Phys....

Cited By (since 1996): 2, Export Date: 23 October 2012, Source: Scopus

We describe a method to produce MgB2 bulk via a microwave processing, which has not been reported yet for this material. We used two experimental arrangements, which were different in the form of the graphite thermal activator responsible for the microwave absorption. The reaction products have been analyzed from the morphological, structural and e...

We report the growth of highly oriented microscopic whisker-like crystals in the Bi-Sr-Ca-Cu-O system by means of glassy precursors. The dependence of the growth on the stoichiometric composition and on the temperature and duration of the annealing process has been studied. Chemical impurities have been investigated from the point of view of the mo...

We have developed a reliable method based on AC magnetic susceptibility measurements to determine the Bi2Sr2Ca2Cu3O10+x (2223) phase volume fraction and the average grain radius in multiphasic polycrystalline Bi–Sr–Ca–Cu–O samples. Precision and applicability of the method are discussed and compared with those of the XRD peak integration procedure....

A new theory is presented concerning both IBIC (ion beam induced charge) and IBIL (ion beam induced luminescence) as obtained by a few MeV ion microbeam of a few micrometers spot size. The theory evidences the fact that IBIL depends on the ratio between the total carrier lifetime and the radiative recombination lifetime. The IBIL/IBIC maps, as obta...

We have investigated the production of the BSCCO 2223 phase by using four different types of starting chemical compounds with the same thermal treatment. Samples have been characterised in various aspects, and the 2223 phase volume fractions have been accurately determined by applying the effective medium theory to magnetic susceptibility measureme...

Diamond has many attractive properties which make it an ideal material both for particle detection in high-energy physics experiments and for dosimetry in medical fields. Up to early 1990, diamond has not found widespread applications in these fields because of the high cost and of the difficulties in selecting natural gems of suitable quality, wit...

Ion micro-beams are very efficient probes to characterize wide gap semiconductors. Ion beam induced charge (IBIC) technique has been extensively used to investigate the transport properties of diamond samples. Due to its scintillating nature, diamond is also suitable to be characterized by ionoluminescence. Similar to cathodoluminescence, this tech...

A new version of the classical IBIC technique is presented together with a comparison between IBIC and IBIL microscopy with the aim of obtaining maps of radiative recombination centers in technologically advanced materials. In some cases (Si,CCdTe) the method is used to profile the electrical field in the bulk of the sample, in other cases (GaAs, C...

Diamond is a very attractive material for use as a radiation detector due to its inertness, radiation hardness and tissue equivalence. The development of diamond radiation detectors was limited by the availability of good and reproducible natural samples. The advent of chemical vapour deposition techniques has allowed these drawbacks to be overcome...

The noise spectrum of the magnetoresistivity in the breakdown of the Integral Quantum Hall Effect (IQHE) at high currents is studied in wide high-quality GaAs/AlGaAs heterostructures on thei=2 Hall plateau, in particular for values of current and/or magnetic field at which pronounced steps and striking temporal patterns showing switching between di...

The breakdown of the integral quantum Hall effect at high current is studied in wide high-quality GaAs/AlxGa1-xAs heterostructures, on the i=2 and i=4 Hall plateaus. The striking features of the phenomenon are pronounced steps in longitudinal resistance with rich time-dependent structures, which are analyzed with techniques normally applied to the...