Alek Dediu

Alek Dediu
Italian National Research Council | CNR · Institute of Nanostructured Materials - ISMN Bologna

PhD

About

152
Publications
15,650
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6,005
Citations
Additional affiliations
January 1993 - December 1997
Abdus Salam International Centre for Theoretical Physics
Position
  • PostDoc Position

Publications

Publications (152)
Article
Full-text available
Multifunctional and resistant 3D structures represent a great promise and a great challenge in bone tissue engineering. This study addresses this problem by employing polycaprolactone (PCL)-based scaffolds added with hydroxyapatite (HAp) and superparamagnetic iron oxide nanoparticles (SPION), able to drive on demand the necessary cells and other bi...
Article
The inorganic/molecular spinterface is an ideal platform for generating extraordinary spin effects. Understanding and controlling these spin-related effects is mandatory for the exploitation of such interfaces in devices. For this purpose we have investigated the adsorption of α-sexithiophene (α-6T) on La0.7Sr0.3MnO3 (LSMO) as one of the prototypic...
Article
We have probed the structural and magnetic properties of a ferromagnetic/organic interface constituted by a polycrystalline Co layer deposited on a fullerene thin film through resonant soft X-ray reflectivity measurements. The fitting analysis of the reflectivity indicates the formation of a sharp interface with limited intermixing and a null reman...
Article
Full-text available
A three dimensional magnetic patterning of two cell types was realised in vitro inside an additive manufactured magnetic scaffold, as a conceptual precursor for the vascularised tissue. The realisation of separate arrangements of vascular and osteoprogenitor cells, labelled with biocompatible magnetic nanoparticles, was established on the opposite...
Article
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We combine time-resolved pump-probe magneto-optical Kerr effect and photoelectron spectroscopy experiments supported by theoretical analysis to determine the relaxation dynamics of delocalized electrons in half-metallic ferromagnetic manganite La1−xSrxMnO3. We observe that the half-metallic character of La1−xSrxMnO3 determines the timescale of both...
Preprint
Full-text available
We combine time resolved pump-probe Magneto-Optical Kerr Effect and Photoelectron Spectroscopy experiments supported by theoretical analysis to determine the relaxation dynamics of delocalized electrons in half-metallic ferromagnetic manganite $La_{1-x}Sr_{x}MnO_{3}$. We observe that the half-metallic character of $La_{1-x}Sr_{x}MnO_{3}$ determines...
Article
Full-text available
Since its discovery in early 2000’s Molecular Spintronics has developed in an established and fructuous research field, achieving a number of outstanding results and unveiling unusual spintronic properties. Typically the most mysterious device element, the interface, in molecular spintronics has on contrary received and enormous attention and even...
Preprint
Full-text available
The understanding of magnetoresistance (MR) in organic spin valves (OSVs) based on molecular semiconductors is still incomplete after its demonstration more than a decade ago. While carrier concentration may play an essential role in spin transport in these devices, direct experimental evidence of its importance is lacking. We probed the role of ch...
Article
Full-text available
The understanding of magnetoresistance (MR) in organic spin valves (OSVs) based on molecular semiconductors is still incomplete after its demonstration more than a decade ago. While carrier concentration may play an essential role in spin transport in these devices, direct experimental evidence of its importance is lacking. We probed the role of ch...
Article
Full-text available
The magnetic and magnetotransport properties of Ni80Fe20/La0.7Sr0.3MnO3 (NiFe/LSMO) bilayers were investigated after bombarding the LSMO surface with low-energy Ar+ or O2+/Ar+ ion beams before the growth of the top NiFe layer. A variety of magnetic properties are revealed, including an asymmetric two-stepped hysteresis loop with an exchange bias lo...
Article
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Spinterface engineering has shown quite important roles in organic spintronics as it can improve spin injection or extraction. In this study, 11,11,12,12‐tetracyanonaptho‐2,6‐quinodimethane (TNAP) is introduced as an interfacial layer for a prototype interface of Fe/TNAP. An element‐specific investigation of the electronic and magnetic structures o...
Preprint
Full-text available
Spinterface engineering has shown quite important roles in organic spintronics as it can improve spin injection or extraction. In this study, 11,11,12,12-tetracyanonaptho-2,6-quinodimethane (TNAP) is introduced as an interfacial layer for a prototype interface of Fe/TNAP. We report an element-specific investigation of the electronic and magnetic st...
Article
Detection of biomarkers in picomolar or subpicomolar concentrations for revealing marker proteins at the early stage of neurodegenerative diseases is an urgent problem. One of the stages of its solution is determination of the marker’s protein layer thickness adhering to the surface of magnetized nanoparticles. In this work, we present an algorithm...
Article
The understanding of spin injection and transport in organic spintronic devices is still incomplete, with some experiments showing magnetoresistance and others not detecting it. We have investigated the transport properties of a large number of tris-(8-hydroxyquinoline)aluminum-based organic spintronic devices with an electrical resistance greater...
Article
Full-text available
Vertical cross-bar devices based on manganite and cobalt injecting electrodes and metal-quinoline molecular transport layer are known to manifest both magnetoresistance and electrical bistability. The two effects are strongly interwoven, inspiring new device applications such as electrical control of the magnetoresistance and magnetic modulation of...
Article
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The synthesis and the chemisorption from solution of a terbium bis-phthalocyaninato complex suitable for the functionalization of lanthanum strontium manganite (LSMO) are reported. Two phosphonate groups are introduced in the double decker structure in order to allow the grafting to the ferromagnetic substrate actively used as injection electrode i...
Article
The miniaturization trend in the semiconductor industry has led to the understanding that interfacial properties are crucial for device behaviour. Spintronics has not been alien to this trend, and phenomena such as preferential spin tunnelling, the spin-to-charge conversion due to the Rashba–Edelstein effect and the spin–momentum locking at the sur...
Article
Full-text available
Molecular spintronics has successfully crossed its first decade of life becoming an important player in the race towards the fabrication of next generation spintronic devices. The development and fabrication of spin OLEDs represents one of the key challenges in this area. Indeed, combining spin polarised injection with light emission is expected to...
Article
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We introduce an innovative approach to the simultaneous control of growth mode and magnetotransport properties of manganite thin films, based on an easy-to-implement film/substrate interface engineering. The deposition of a manganite seed layer and the optimization of the substrate temperature allows a persistent bi-dimensional epitaxy and robust f...
Article
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A novel functionalization of a ferromagnetic electrode employed in spintronic devices is reported. Self-assembling monolayer technique has been used to chemisorb a paramagnetic phosphonate functionalized nitronyl-nitroxide radical (NitPO) on the ferromagnetic La0.7Sr0.3MnO3 (LSMO) manganite surface. This interfacial layer causes clearly detectable...
Article
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The fascinating prospect to direct tissue regeneration by magnetic activation has been recently explored. In this study we investigate the possibility to boost bone regeneration in an experimental defect in rabbit femoral condyle by combining static magnetic fields and magnetic biomaterials. NdFeB permanent magnets are implanted close to biomimetic...
Article
In the past few years, researchers have focused on the design and development of three-dimensional (3D) advanced scaffolds, which offer significant advantages in terms of cell performance. The introduction of magnetic features into scaffold technology could offer innovative opportunities to control cell populations within 3D microenvironments, with...
Article
Achieving an efficient fixation for complicated fractures and scaffold application treatments is a challenging surgery problem. Although many fixation approaches have been advanced and actively pursued, the optimal solution for long bone defects has not yet been defined. This paper promotes an innovative fixation method based on application of magn...
Article
Full-text available
Magnetic silk fibroin protein (SFP) scaffolds integrating magnetic materials and featuring magnetic gradients were prepared for potential utility in magnetic-field assisted tissue engineering. Magnetic nanoparticles (MNPs) were introduced into SFP scaffolds via dip coating methods, resulting in magnetic SFP scaffolds with different strengths of mag...
Article
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We derive kinetic equations describing injection and transport of spin polarized carriers in organic semiconductors with hopping conductivity via an impurity level. The model predicts a strongly voltage dependent magnetoresistance, defined as resistance variation between devices with parallel and antiparallel electrode magnetizations (spin valve ef...
Article
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Nanoindentation can provide new insights on the maturity stage of regenerating bone. The aim of the present study was the evaluation of the nanomechanical properties of newly-formed bone tissue at 4 weeks from the implantation of permanent magnets and magnetic scaffolds in the trabecular bone of rabbit femoral condyles. Three different groups have...
Article
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The outgrowth formation in inorganic thin films is a dramatic problem that has limited the technological impact of many techniques and materials. Outgrowths are often themselves part of the films, but are detrimental for vertical junctions since they cause short-circuits or work as defects, compromising the reproducibility and in some cases the ope...
Article
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In this article we present the morphological and magnetic characterization of ferrofluid-impregnated biomimetic scaffolds made of hydroxyapatite and collagen used for bone reconstruction. We describe an innovative and simple impregnation process by which the ferrofluid is firmly adsorbed onto the hydroxyapatite/collagen scaffolds. The process confe...
Article
The design and fabrication of advanced biocompatible and bioresorbable materials able to mimic the natural tissues present in the human body constitutes an important challenge in regenerative medicine. The size-dependent properties that materials exhibit at the nanoscale as a consequence of their higher surface-to-volume ratio have opened a wide ra...
Article
Ferromagnetic metal-organic semiconductor (FM-OSC) hybrid interfaces have shown to play an important role for spin injection in organic spintronics. Here, 11,11,12,12-tetracyanonaptho-2,6-quinodimethane (TNAP) is introduced as an interfacial layer in Co-OSCs heterojunction with an aim to tune the spin injection. The Co/TNAP interface is investigate...
Article
Full-text available
We investigated the growth mechanism of pentacene thin films on La0.7Sr0.3MnO3. A diffusion limited, thermally activated growth was found. Pentacene molecules formed flat islands that were a few microns in size and whose growth during deposition showed a strong anisotropy. We extracted a nucleation energy of 0.65 ± 0.05 eV and a diffusion barrier e...
Article
We present a novel method of delivering a low-concentration (<15%) ozone beam to an ultra-high vacuum environment for the purpose of cleaning and dosing experimental samples through oxidation processing. The system described is safe, low-cost, and practical and overcomes the limitations of ozone transport in the molecular flow environment of high o...
Article
A number of studies have suggested that molecular materials could offer similar performance as, or even potentially supersede, those of inorganic materials in spintronics devices. Radically new spintronics functionalities, unavailable with conventional inorganic materials, could stem from the interface between ferromagnetic (FM) and molecular mater...
Article
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Ultrathin manganite films are widely used as active electrodes in organic spintronic devices. In this study, a scanning tunnelling microscopy (STM) investigation with atomic resolution revealed previously unknown surface features consisting of small non-stoichiometric islands. Based upon this evidence, a new mechanism for the growth of these comple...
Article
Full-text available
La0.7SrO3MnO3 (LSMO) thin films have proven to act as an efficient spin injection electrode in hybrid organic/inorganic spintronic devices. Optimal control of the chemical composition of the LSMO outermost layer is a key issue in the realization of efficient and reproducible spintronic devices. Low-energy ion scattering (LEIS) and X-ray photoelectr...
Article
A concentration of Manganese as high as 8% was successfully diluted into Zinc Oxide epitaxial films deposited by pulsed laser deposition. The films showed strong ferromagnetism with a large coercivity. Low temperature X-ray absorption spectroscopy measurements indicated that all the Manganese ions substitute for Zinc sites of the wurtzite lattice i...
Article
Thermo switchable magnetic hydrogels undoubtedly have a great potential for medical applications since they can behave as smart carriers able to transport bioactive molecules to a chosen part of the body and release them on demand via magneto-thermal activation. We report on the ability to modify the lower critical solution temperature (LCST) of po...
Article
In biomedicine, magnetic nanoparticles provide some attractive possibilities because they possess peculiar physical properties that permit their use in a wide range of applications. The concept of magnetic guidance basically spans from drug delivery and hyperthermia treatment of tumours, to tissue engineering, such as magneto-mechanical stimulation...
Article
Full-text available
Structural features and magnetic behaviour of TbPc2 thin films sublimated on LSMO and on cobalt surfaces have been investigated by synchrotron-based XNLD and XMCD techniques. Different orientation of the molecules is observed for the two substrates. No significant magnetic interaction with the ferromagnetic substrates is detected.
Article
The mathematical prediction of cell proliferation in porous scaffold still remains a challenge. The analysis of existing models and experimental data confirms a need for a new solution, which takes into account cells" development on the scaffold pore walls as well as some additional parameters such as the pore size, cell density in cellular layers,...
Article
Full-text available
Transport characterizations of epitaxial La0.7Sr0.3MnO3 thin films in the thickness range 5-40 nm and 25-410 K temperature interval have been accurately collected. We show that taking into account polaronic effects allows to achieve the best ever fitting of the transport curves in the whole temperature range. The Current Carriers Density Collapse p...
Article
The fundamental elements of tissue regeneration are cells, biochemical signals and the three-dimensional microenvironment. In the described approach, biomineralized-collagen biomaterial functions as a scaffold and provides biochemical stimuli for tissue regeneration. In addition superparamagnetic nanoparticles were used to magnetize the biomaterial...
Article
A snapshot of electrons crossing a metal/organic interface provides a better understanding of spin filtering and hints at new directions for designing spintronic devices.
Chapter
This chapter describes the experimental achievement which adds conceptually new features to a standard memristor principle. It shows that electrically controlled magnetoresistance can be achieved in organic devices by combining magnetic bistability, GMR effect, and memristive effects. The chapter discusses the La0.7Ca0.3MnO3/ PrBa2Cu3O7/ La0.7Ca0.3...
Conference Paper
Diaphyseal bone defect represents a significant problem for orthopaedic surgeons and patients. In order to improve and fasten bone regenerating process we implanted HA biodegradable magnetized scaffolds in a large animal model critical bone defect. A critical long bone defect was created in 6 sheep metatarsus diaphysis; then we implanted a novel po...
Article
Full-text available
Thermoswitchable magnetic hydrogels are being extensively investigated because of their great potential for medical applications. Indeed, they can behave as smart carriers able to transport drugs to a chosen part of the body and release them via magneto-thermal activation by an external alternating magnetic field. We report on the magnetization of...
Article
Full-text available
Memristors are one of the most promising candidates for future information and communications technology (ICT) architectures. Two experimental proofs of concept are presented based on the intermixing of spintronic and memristive effects into a single device, a magnetically enhanced memristor (MEM). By exploiting the interaction between the memrista...
Article
We report on the optimisation of the growth conditions of manganite La0.7Sr0.3MnO3 (LSMO) thin films prepared by Channel Spark Ablation (CSA). CSA belongs to pulsed electron deposition methods and its energetic and deposition parameters are quite similar to those of pulsed laser deposition. The method has been already proven to provide manganite fi...
Article
Full-text available
We investigate spin precession (Hanle effect) in the prototypical organic spintronic giant magnetoresistance (GMR) device La0.7Sr0.3MnO3(LSMO)/tris(8-hydroxyquinoline)(Alq3)/AlOx/Co. The Hanle effect is not observed in measurements taken by sweeping a magnetic field at different angles from the plane of the device. As possible explanations we discu...
Article
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Many experiments have demonstrated that the spin direction of an electron survives for a relatively long time in an organic material. Results presented at a recent conference show how such long spin-lifetimes can be used in devices.
Article
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Highly-anisotropic in-plane magneto-resistance (MR) in graphite (HOPG) samples has been recently observed (Y. Kopelevich et al., arXiv:1202.5642) which is negative and linear in low fields in some current direction while it is giant, super-linear and positive in the perpendicular direction. In the framework of the hopping conductance theory via non...
Article
Full-text available
In hopping magnetoresistance of doped insulators, an applied magnetic field shrinks the electron (hole) s-wave function of a donor or an acceptor and this reduces the overlap between hopping sites resulting in the positive magnetoresistance quadratic in a weak magnetic field, B. We extend the theory of hopping magnetoresistance to states with nonze...
Article
Scaffold fixation represents one of the most serious challenges in osteochondral defect surgery. Indeed, the fixation should firmly hold the scaffold in the implanted position as well as it should guaranty stable bone/scaffold interface for efficient tissue regeneration. Nonetheless successful results have been achieved for small defect repair, the...
Article
Organic spintronics studies spin carrier transportation through organic semiconductors. Understanding how to control this spin current within devices is an important step forward within the research area. The study of the interfaces between the magnetic electrodes and the organic semiconductor (known as the “spinterface”) to obtain efficient carrie...