Saso Šturm

Saso Šturm
Jožef Stefan Institute | IJS · Department of Nanostructured Materials

PhD

About

123
Publications
18,687
Reads
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1,419
Citations
Introduction
Core expertise in high-resolution TEM/STEM imaging (HRTEM, BF/ABF/ADF STEM) and spectroscopy (EELS, EDXS) with a focus on nanomaterials and interfaces at the atomic scale. Current focus on various aspects of in-situ TEM techniques; in-situ heating/cooling and liquid TEM. Material processing: Solid state synthesis of functional ceramics, Hydrothermal synthesis of nanomaterials.
Additional affiliations
January 1998 - present
Jožef Stefan Institute
Position
  • Head of Department

Publications

Publications (123)
Article
Full-text available
Ammonia (NH3) present in biological fluids is biomarker for several disease states. In this work the well-known interaction between polyaniline (PANI) and NH3 was used for the fabrication of an amperometric sensory platform to detect aqueous NH3 at neutral i.e. biological pH. Understanding PANI's electrochemical synthesis and redox behaviour in aci...
Conference Paper
The investigation of the nucleation and dissolution of gold nanoparticles on a glassy carbon substrate with Scanning Electrochemical Cell Microscopy (SECCM) combined with in-situ electrochemical TEM (EC-TEM) revealed the subtle influence of the local properties of the substrate on the electrochemical processes. Conducting hundreds of locally-resolv...
Article
Full-text available
The consumption of critical raw materials, especially those in permanent magnets of Nd–Fe–B and Sm–Co-type, has significantly grown in the past decade. With predictions on further electrification growing exponentially the demand for these materials will even increase. This implies that efforts in assuring sustainability must involve recycling from...
Article
A binary phase with Al4Ir composition has been discovered in the Al-Ir binary system. Single-crystal X-ray diffraction analysis reveals that it crystallizes in the trigonal space group P3c1 with the unit cell parameters a = 12.8802(2) Å and c = 9.8130(2) Å. This structure is derived from the Ni2Al3 structure type. The supercell is due to the orderi...
Article
Full-text available
Despite medical advances, skin-associated disorders continue to pose a unique challenge to physicians worldwide. Skin cancer is one of the most common forms of cancer, with more than one million new cases reported each year. Currently, surgical excision is its primary treatment; however, this can be impractical or even contradictory in certain situ...
Article
The formation of two-dimensional oxide dodecagonal quasicrystals as well as related complex approximant phases were recently reported in thin films derived from BaTiO 3 or SrTiO 3 perovskites deposited on (111)-oriented Pt...
Article
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This study focused on the crystal and electronic structures of a newly discovered phase in the Al-Cr-Sc system. The latter two species do not mix in a binary alloy, but can be alloyed with aluminium in the vicinity of the Al2−xCrxSc composition, where 0.3 < x < 0.5. After preparation of the pure constituents via arc melting, high-temperature anneal...
Article
In this work, we present a newly developed, economically efficient method for processing rare-earth Nd-Fe-B magnets based on spark plasma sintering. It makes us possible to retain the technologically essential properties of the produced magnet by consuming about 30% of the energy as compared to the conventional SPS process. A magnet with anisotropi...
Article
Full-text available
Photothermal therapy has always been a very attractive anti-cancer strategy, drawing a lot of attention thanks to its excellent performance as a non-invasive and pretty safe technique. Lately, nanostructures have become the main characters of the play of cancer therapy due to their ability to absorb near-infrared radiation and efficient light-to-he...
Article
The magnetic properties of an Nd-Fe-B-type permanent magnet depend on the microstructure and the chemistry of the material. To compensate for unfavorable microstructural features, such as micron-sized grains of the hard-magnetic phase, the intrinsic coercivity is often enhanced by the addition of heavy-rare-earth elements, but these additions also...
Article
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The main challenge with electrocatalysis is finding low-cost electrocatalysts that can work efficiently to oxidize the HCHO. Here, we propose a mechanism for the voltammetric formation of a highly active, structurally disordered β-Ni(OH)2/β-NiOOH redox pair on the surface of electrodeposited Ni thin films to achieve an extraordinary catalytic perfo...
Article
Full-text available
We propose a dominant core-shell formation mechanism for grain-boundary-diffusion-processed (GBDP), Tb-treated, Nd2Fe14B sintered magnets. A depth-sensitive analysis of Tb-treated samples, relative to a non-GBDP Nd2Fe14B magnet, showed a 30% increase of the coercivity in the central part of the magnet. A structure-chemistry-magnetic-property analys...
Article
Full-text available
Polyaniline (PANI) is a conducting polymer, widely used in gas-sensing applications. Due to its classification as a semiconductor, PANI is also used to detect reducing ammonia gas (NH3), which is a well-known and studied topic. However, easier, cheaper and more straightforward procedures for sensor fabrication are still the subject of much research...
Article
Full-text available
In present work, we report on the enhanced electrocatalytic activity of formaldehyde oxidation in alkaline media for modified Ni nanowires (NWs)-based electrodes. Electrochemically deposited Ni NWs composed of metallic Ni and surface NiO were modified in KOH via cyclic voltammetry using different scan rates (10, 200 and 400 mV s⁻¹) in order to tran...
Article
We have produced hot-deformed Nd-Fe-B magnets from commercial (MQU-F) Nd-Fe-B ribbons. The spark-plasma-sintering technique was used to deform the samples under low pressures of 40 MPa. The initial stages of the hot-deformation process were investigated in terms of microstructures and magnetic properties. Hot-deformed magnets with different deforma...
Article
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Three phases can be distinguished in Nd‒Fe‒B permanent magnets: a Nd2Fe14B matrix grain phase, a Nd-rich grain boundary phase and a Nd-oxide phases. Common reaction models for leaching, such as the shrinking-particle model, cannot simply be applied to composite Nd‒Fe‒B permanent magnets because of the different chemical reactivities of the crystall...
Article
Sintered Nd-Fe-B permanent magnets are the first choice for electro-mechanical devices that rely on hard-magnetic materials to provide strong magnetic fields in a variety of operating conditions. However, the limitations of conventional powder-metallurgy methods regarding the complexity of the magnet’s geometry restrict the design freedom for elect...
Article
B has been proposed to extend persistent luminescence from minutes to > 10 h in Eu, Dy, and B co-doped Sr4Al14O25 (S4A7EDB) by facilitating the incorporation of Eu²⁺ and Dy³⁺ into adjacent Sr sub-lattice sites and enabling energy transfer between them. To evaluate additional influences of B on the kinetics of microstructural evolution and dopant di...
Article
Full-text available
A closed loop of recovering rare-earth elements and transition metals from Nd–Fe–B magnets with the total re-use of the electrolyte using a facile electrolysis-selective precipitation procedure.
Article
A new ternary phase with a composition Al1+xV2Sn2-x (x = 0.19) has been found during investigation of the Al-V-Sn ternary system. Single-crystal X-ray diffraction measurements reveal that this ternary phase crystallizes with an orthorhombic structure with a = 5.5931(1) Å, b = 18.8017(5) Å, and c = 6.7005(2) Å (space group Cmce). This compound is th...
Article
Full-text available
Recycling of end‐of‐life Nd–Fe–B magnets is an important strategy for reducing the environmental dangers associated with rare‐earth mining and overcoming the supply risks associated with the rare‐earth elements. In this study, a novel concept for recycling of sintered Nd–Fe–B magnets by directly recovering the matrix Nd 2 Fe 14 B grains is presente...
Article
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With Liquid-Cell Transmission Electron Microscopy (LCTEM) we can observe the kinetic processes taking place in nanoscale materials that are in a solvated environment. However, the beam-driven solvent radiolysis, which results from the microscope's high-energy electron beam, can dramatically influence the dynamics of the system. Recent research sugg...
Article
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Ceramic pigments emitting long afterglow have enormous potential for emerging lighting applications that consume zero energy from the power grid. One of the most efficient compounds is strontium aluminate, when co-doped with 2 rare-earth elements — an optically active emitter, such as Eu2+, and an auxiliary ion, such as Dy3+— and B. To date, spectr...
Article
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The magnetic properties of the recycled hydrogenation disproportionation desorption recombination (HDDR) Nd-Fe-B powder, doped with a low weight fraction of DyF 3 nanoparticles, were investigated. Spark plasma sintering (SPS) was used to consolidate the recycled Nd-Fe-B powder blends containing 1, 2, and 5 wt.% of DyF 3 grounded powder. Different p...
Article
The Cover Feature demonstrates the induced deposition of rare earth element (REE) catalyzed by the activated‐state transition metal (TM).More information can be found in the Article by X. Xu et al.
Article
Highly ordered, Ni(OH) 2 [sbnd]Ni-nanowire-based receptor elements were electrochemically fabricated and tested for formaldehyde (HCHO) detection by monitoring their oxidation ability in alkaline media. In order to normalize the electrochemical output currents, the Ni nanowires' electrochemically active surface area was assessed using an oxalate-ba...
Article
Full-text available
Rare earth element (REE)‐based metals and alloys are generally synthesized by molten‐salt electrolysis which is an energy‐intensive approach. Previous attempts to deposit alloys of rare earths from solutions at mild temperatures have met with little success. Excitingly, in this investigation we were able to electrodeposit Nd–Fe from the 1‐ethyl‐3‐m...
Article
Full-text available
The dependence of the magnetic properties on the particle size of recycled HDDR Nd-Fe-B powders were investigated, with the aim to assess the reprocessing potential of the end-of-life scrap magnets via spark plasma sintering (SPS). The as received recycled HDDR powder had coercivity (HCi) = 830 kA/m and particles in the range from 30 – 700 µm (aver...
Article
Full-text available
The goal of this study was to justify the reprocessing of recycled HDDR Nd-Fe-B powders with spark plasma sintering (SPS) and to investigate the dependence of the final magnetic properties on SPS and thermal treatment. The initial recycled HDDR powder of the composition Nd13.4Dy0.6Fe78.6B6.1Nb0.4Al0.7 with 4760 ppm O2 content, coercivity (HCi) = 83...
Article
This study confirms that the stable icosahedral quasicrystal (iQc) phase Al65Cu20Fe15 (iQc–AlCuFe) can serve as a substrate for the nucleation of the metastable iQc–AlMnSi phase formed in rapidly solidified Al–Mn–Si alloys. The results reveal that a continuous, thin layer of the metastable iQc–AlMnSi phase can be formed on a stable iQc–AlCuFe parti...
Article
Spark plasma sintering (SPS) technique is applied in combination with hydrogen decrepitation process for the recycling of SmCo5 magnets. The SmCo5 magnets for recycling were first decrepitated by hydrogen gas of a pressure of 4 bar for 3 hours to produce decrepitated powder. This powder was then used to prepare isotropic sintered magnets using the...
Article
Full-text available
A detailed magnetic study of separated Fe–Pt NPs and Fe–Pt clusters was performed to predict their optimal size and morphology for the maximum saturation magnetization, a factor that is known to influence the performance of a magnetic-resonance-imaging (MRI) contrast agent. Excellent stability and biocompatibility of the nanoparticle suspension was...
Article
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The basic and the charge density wave (CDW) structures of the monoclinic $NbS_3-II$ polymorph were studied by synchrotron x-ray diffraction, ab-initio calculation, simulation of electron diffraction patterns and by atomic-resolution transmission electron and low-temperature scanning tunneling microscopies. It is shown that the basic structure belon...
Article
Iron and copper are immiscible elements, but can be combined in the presence of a third element such as aluminium or cerium. We varied the additions of immiscible Fe and Cu (ratio y) in the stoichiometric Al20.5Ce41.5(FeyCu1 − y)38 alloys in order to trace their impact on the structure, microstructure, thermal properties and magnetism. By powder X-...
Article
Fe69±3Pd31±3 nanowires (NWs) with lengths of a few microns and diameters of 200 nm were synthesized via template-assisted pulsed electrodeposition into alumina-based templates. The as-deposited Fe69±3Pd31±3 NWs exhibited α-Fe (bcc-solid solution of Fe, Pd) nanocrystalline structure as seen from the x-ray diffraction (XRD), that got confirmed by tra...
Article
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p class="PaperAbstract">It is shown in this overview that modern composition depth profiling methods like secondary neutral mass spectroscopy (SNMS) and glow-discharge – time-of-flight mass spectrometry (GD-ToFMS) can be used to gain highly specific composition depth profile information on electrodeposited alloys. In some cases, cross-sectional tra...
Article
Composition evolution and structural properties of Fe-Co-Ni thin films have been studied by transmission electron microscopy along the growth direction. The samples were electrodeposited with constant current from stagnant solution. The samples were of uneven composition, exhibiting two major modes of composition change: a near-substrate compositio...
Article
We have produced an innovative, theranostic material based on FePt/SiO2/Au hybrid nanoparticles (NPs) for both, photo-thermal therapy and magnetic resonance imaging (MRI). Furthermore, a new synthesis approach, i.e., Au double seeding, for the preparation of the Au nanoshells around the FePt/SiO2 cores, is proposed. The photo-thermal and the MRI re...
Article
The uniaxial strain of quasi-one-dimensional conductor whiskers of orthorhombic TaS3 at a strain higher than εc ~ 0.8% leads to a sharp increase in the coherence of the properties of a charge density wave (CDW), which manifests itself in its motion in fields higher than threshold field Et. During uniaxial elongation, TaS3 is shown to exhibit the fo...
Chapter
Nanomedical approaches in cancer treatment have the potential to enhance the effectiveness of localized therapy while minimizing side effects on the surrounding healthy tissue. The aim of our study was the development of a novel hybrid nanoparticles (hNPs) based on magnetic core (FePt) and photothermaly active shell (SiO2/Au) for targeting of cance...
Conference Paper
It is known that thermoelectric properties, i.e. figure of merit ZT of oxide-based polycrystalline thermoelectric materials can be improved by introducing planar faults into the microstructure of these materials. It is assumed that in-grown planar faults will reduce thermal conductivity without reducing electrical properties which would consequentl...
Chapter
Yttria, a host for heavy rare earth elements, is an important up-conversion material, able to convert lower energy near-infrared light into higher energy visible light, opening the avenue for a wide spectrum of applications from laser technology, photovoltaics to theranostics [1,2]. The efficient use of yttria in the form of nanoparticles (NPs) is...
Chapter
Yttrium oxide (Y2O3) nanoparticles (NPs) as a host for heavy rare earth elements (Yb3+, Eu3+) have shown to be an efficient up-conversion phosphor material with a great potential ranging from therapy and sensing for drug delivery to photovoltaic applications [1]. In order to achieve desired morphology and size distribution of Y2O3 NPs the nucleatio...
Article
Processes taking place during hydrogen desorption from MgH2 thin films were investigated in as-prepared samples and samples modified by argon ion irradiation. Irradiation was used to produce well-defined defects with depth distribution. It was shown that the size, shape, and concentration of Mg nuclei formed during hydrogen desorption from MgH2 thi...
Article
The present work describes the formation of amorphous alloys in the (Al1−xCex)62Cu25Fe13 quaternary system (0 ≤ x ≤ 1). When the amount of Ce falls in the range 0.67 ≤ x ≤ 0.83, the alloys obtained exhibit a completely amorphous structure confirmed by powder X-ray diffraction. Otherwise, at compositions x = 0.5, 0.58, 0.92 and 1, a primary crystall...
Article
Through transport, compositional and structural studies, we review the features of the charge-density wave (CDW) conductor of NbS$_{3}$ (phase II). We highlight three central results: 1) In addition to the previously reported CDW transitions at $T_{P1}$ = 360\,K and $T_{P2}$ = 150\,K, another CDW transition occurs at a much higher temperature $T_{P...
Article
Full-text available
Undoped and Nb-, K- or Li-doped TiO2 nanopowders were synthesized using a bottom-up approach by sol–gel method. The changes of crystal structure in TiO2 upon Nb, K or Li doping were followed with X-ray diffraction (XRD) and Raman spectroscopy techniques. XRD results have shown that anatase-to-rutile phase transition as a function of temperature was...
Article
Full-text available
Flash sintering experiments were performed, for the first time, on sodium potassium niobate (KNN) ceramics. A theoretical density of 94% was achieved in 30 s under 250 V/cm electric-field at 990°C. These conditions are ∼100°C lower and faster than the conventional sintering conditions. Grains tended to grow after 30 s. flash sintering duration unde...
Article
Long persistence phosphors are promising materials for energy-saving applications, due to their ability to temporarily store and release light. While boron is known to dramatically extend the afterglow persistence to longer than 8 h in strontium aluminates, previous attempts to understand the role of boron neglected any nanoscale-related effects an...
Article
Pure copper and Cu−11.4 wt.%Au alloy were obtained by a powder metallurgy (PM) technique and subjected to thermomechanical treatment that was used to produce the conditions that led to an anneal hardening effect in the alloy. The results showed that low-temperature annealing of cold-rolled alloy caused a two-stage increase in hardness, microhardnes...
Article
Full-text available
The value of the magnetization has a strong influence on the performance of nanoparticles that act as the contrast agent material for MRI. In this article, we describe processing routes for the synthesis of FePt nanoparticles of different sizes, which, as a result, exhibit different magnetization values. “Single-core” FePt nanoparticles of differen...
Article
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The first one-step synthesis of dumbbell-like gold-iron oxide nanoparticles has been reported here. Surface functionalization with a biocompatible chitosan matrix allowed us to obtain a novel targetable diagnostic and therapeutic tool.
Article
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Using electrodeposition into anodic aluminium oxide (AAO) membranes we have successfully fabricated near-equiatomic Fe48+3Pd52+3 nanowires (NWs) with diameters of ≈ 200 nm and lengths of ≈ 3.5 um. XRD and TEM/SAED analyses revealed that the as-deposited NWs are isotropic and polycrystalline with an average crystal size of 5 nm and have an fcc cryst...
Article
Full-text available
Near equiatomic Fe52±3Pd48±3 nanowires (NWs) with the length of 3.5 $mu text{m}$ and diameter of $approx 200$ nm were potentiostatically deposited at −1.1 V for 900 s into a porous anodic aluminum oxide template. Cylindrical NWs with a consistent composition along their length were obtained after introducing two additional steps prior to the electr...