Search

Your search keyword '"Dediu, Valentin Alek"' showing total 26 results
Start Over Author "Dediu, Valentin Alek"
26 results on '"Dediu, Valentin Alek"'

4. Controlling magnetoresistance by oxygen impurities in Mq3-based molecular spin valves

Author

Riminucci, Alberto, Yu, Zhi-Gang, Prezioso, Mirko, Cecchini, Raimondo, Bergenti, Ilaria, Graziosi, Patrizio, and Dediu, Valentin Alek

Subjects
Physics - Applied Physics
Abstract

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 charge carrier concentration by studying the interplay between MR and multilevel resistive switching in OSVs. The present work demonstrates that all salient features of these devices, particularly the intimate correlation between MR and resistance, can be accounted for by the impurity band model, based on oxygen migration. Finally, we highlight the critical importance of carrier concentration in determining spin transport and MR in OSVs and the role of interface-mediated oxygen migration in controlling the OSVs response.

Published
2019
Full Text
View/download PDF

5. Glassy Synaptic Time Dynamics in Molecular La0.7Sr0.3MnO3/Gaq3/AlOx/Co Spintronic Crossbar Devices

Author

Shumilin, Andrei, primary, Neha, Prakriti, additional, Benini, Mattia, additional, Rakshit, Rajib, additional, Singh, Manju, additional, Graziosi, Patrizio, additional, Cecchini, Raimondo, additional, Gnoli, Luca, additional, Prezioso, Mirko, additional, Bergenti, Ilaria, additional, Dediu, Valentin Alek, additional, and Riminucci, Alberto, additional

Published
2024
Full Text
View/download PDF

7. Spin injection in the doped bad metal SrTiO3

Author

Graziosi, Patrizio, primary, Bergenti, Ilaria, additional, Vistoli, Lorenzo, additional, Galassi, Fabio, additional, Calbucci, Marco, additional, Riminucci, Alberto, additional, Borgatti, Francesco, additional, MacLaren, Donald A., additional, O’Shea, Kerry J., additional, Vinai, Giovanni, additional, Torelli, Piero, additional, Panaccione, Giancarlo, additional, Kabanov, Viktor, additional, and Dediu, Valentin Alek, additional

Published
2023
Full Text
View/download PDF

8. A novel picture for charge transport interpretation in epitaxial manganite thin films

Author

Graziosi, Patrizio, Gambardella, Alessandro, Prezioso, Mirko, Riminucci, Alberto, Bergenti, Ilaria, Pullini, Daniele, Busquets-Mataix, David, and Dediu, Valentin Alek

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

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 picture accurately accounts for the properties variation across the metal-insulator-transition. The electron-phonon coupling parameter estimations are in a good agreement with theoretical predictions. The results promote a clear and straightforward quantitative description of the manganite films involved in charge transport device applications., Comment: Original work on transport data fitting in metallic manganites thin films; 12 pages, 3 figures, 1 table; submitted work

Published
2013

9. Conditions for the growth of smooth La0.7Sr0.3MnO3 thin films by pulsed electron ablation

Author

Graziosi, Patrizio, Prezioso, Mirko, Gambardella, Alessandro, Kitts, Catherine, Rakshit, Rajib Kumar, Riminucci, Alberto, Bergenti, Ilaria, Borgatti, Francesco, Pernechele, Chiara, Solzi, Massimo, Pullini, Daniele, Busquets-Mataix, David Jeronimo, and Dediu, Valentin Alek

Subjects
Condensed Matter - Materials Science, Condensed Matter - Other Condensed Matter
Abstract

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 films with good magnetic properties, but the films were generally relatively rough (a few nm coarseness). Here we show that increasing the oxygen deposition pressure with respect to previously used regimes, reduces the surface roughness down to unit cell size while maintaining a robust magnetism. We analyse in detail the effect of other deposition parameters, like accelerating voltage, discharging energy, and temperature and provide on this basis a set of optimal conditions for the growth of atomically flat films. The thicknesses for which atomically flat surface was achieved is as high as about 10-20 nm, corresponding to films with room temperature magnetism. We believe such magnetic layers represent appealing and suitable electrodes for various spintronic devices., Comment: original paper, thin film optimization, 25 pages, 9 figures

Published
2012
Full Text
View/download PDF

10. Bone Regeneration Guided by a Magnetized Scaffold in an Ovine Defect Model

Author

Maglio, Melania, primary, Sartori, Maria, additional, Gambardella, Alessandro, additional, Shelyakova, Tatiana, additional, Dediu, Valentin Alek, additional, Santin, Matteo, additional, Piñeiro, Yolanda, additional, López, Manuel Bañobre, additional, Rivas, Josè, additional, Tampieri, Anna, additional, Sprio, Simone, additional, Martini, Lucia, additional, Gatti, Alessandro, additional, Russo, Alessandro, additional, Giavaresi, Gianluca, additional, and Fini, Milena, additional

Published
2023
Full Text
View/download PDF

11. Synthesis and Characterization of a Biocompatible Nanoplatform Based on Silica-Embedded SPIONs Functionalized with Polydopamine

Author

Romano, Miriam, primary, González Gómez, Manuel Antonio, additional, Santonicola, Pamela, additional, Aloi, Noemi, additional, Offer, Svenja, additional, Pantzke, Jana, additional, Raccosta, Samuele, additional, Longo, Valeria, additional, Surpi, Alessandro, additional, Alacqua, Silvia, additional, Zampi, Giuseppina, additional, Dediu, Valentin Alek, additional, Michalke, Bernhard, additional, Zimmerman, Ralf, additional, Manno, Mauro, additional, Piñeiro, Yolanda, additional, Colombo, Paolo, additional, Di Schiavi, Elia, additional, Rivas, José, additional, Bergese, Paolo, additional, and Di Bucchianico, Sebastiano, additional

Published
2022
Full Text
View/download PDF

14. In-Depth NMR Investigation of the Magnetic Hardening in Co Thin Films Induced by the Interface with Molecular Layers

Author

Benini, Mattia, Allodi, Giuseppe, Surpi, Alessandro, Riminucci, Alberto, Lin, Ko-Wei, Sanna, Samuele, Dediu, Valentin Alek, Bergenti, Ilaria, Benini, M, Allodi, G, Surpi, A, Riminucci, A, Lin, KW, Sanna, S, Dediu, VA, and Bergenti, I

Subjects
C60, Mechanics of Materials, Mechanical Engineering, Gaq3, solid-state nuclear magnetic resonance (NMR), spinterfaces, cobalt
Abstract

The hybridization of the surface orbitals of thin ferromagnetic layers with molecular orbitals represents a soft but efficient technology that is able to induce in ferromagnetic component radical modifications of the key magnetic parameters, such as magnetization, magnetic anisotropy, and others. These effects are investigated in 7 nm thick polycrystalline Co films interfaced with C-60 and Gaq(3) molecular layers by combining Co-59 Ferromagnetic nuclear resonance spectroscopy (FNR) and magneto-optic kerr effect (MOKE) techniques. It is demonstrated that the surface hybridization produces a significant magnetic hardening with respect to a reference Co/Al system and that the molecule-induced effects modify the magnetic properties of entire Co layer, propagating for several nm from the interface. The FNR spectroscopy also reveals a reconstruction of the magnetic environment at the cobalt surface, whose observation in polycrystalline films is especially intriguing. The results shed new and unexpected light on the interfacial physics in such systems, whose understanding necessitates further experimental and theoretical research.

Published
2022

15. Multifunctional 3D-Printed Magnetic Polycaprolactone/Hydroxyapatite Scaffolds for Bone Tissue Engineering

Author

Petretta, Mauro, primary, Gambardella, Alessandro, additional, Desando, Giovanna, additional, Cavallo, Carola, additional, Bartolotti, Isabella, additional, Shelyakova, Tatiana, additional, Goranov, Vitaly, additional, Brucale, Marco, additional, Dediu, Valentin Alek, additional, Fini, Milena, additional, and Grigolo, Brunella, additional

Published
2021
Full Text
View/download PDF

20. An Organic Spin Valve Embedding a Self-Assembled Monolayer of Organic Radicals

Author

Poggini, Lorenzo, primary, Cucinotta, Giuseppe, additional, Pradipto, Abdul-Muizz, additional, Scarrozza, Marco, additional, Barone, Paolo, additional, Caneschi, Andrea, additional, Graziosi, Patrizio, additional, Calbucci, Marco, additional, Cecchini, Raimondo, additional, Dediu, Valentin Alek, additional, Picozzi, Silvia, additional, Mannini, Matteo, additional, and Sessoli, Roberta, additional

Published
2016
Full Text
View/download PDF

23. Publisher's Note: “Low intrinsic carrier density LSMO/Alq3/AlOx/Co organic spintronic devices” [Appl. Phys. Lett. <bold>112</bold>, 142401 (2018)].

Author

Riminucci, Alberto, Graziosi, Patrizio, Calbucci, Marco, Cecchini, Raimondo, Prezioso, Mirko, Borgatti, Francesco, Bergenti, Ilaria, and Dediu, Valentin Alek

Subjects
CARRIER density, SPINTRONICS
Abstract

A correction to the affiliation of one of the authors of the article "Low intrinsic carrier density LSMO/Alq3/AlOx/Co organic spintronic devices," originally published online on April 2, 2018 is presented.

Published
2018
Full Text
View/download PDF

24. Organic spintronics: Inside the interface.

Author

Dediu, Valentin Alek

Subjects
*INTERFACES (Physical sciences), *ELECTRODES, *SPINTRONICS, *SPIN (Aerodynamics), *RESEARCH
Abstract

The author discusses research on the mechanism of carrier transfer inside an interface consisting of a hard metallic electrode touching a soft organic layer. It references a study by Sabine Steil and colleagues published in a 2013 issue of "Nature Physics." He believes that a snapshot of electrons crossing a metal/organic interface provides implications for spin filtering and spintronic device design.

Published
2013
Full Text
View/download PDF

25. Application of magnetic rods for fixation in orthopedic treatments

Author

Alessandro Russo, Tatiana Shelyakova, Maurilio Marcacci, Andrea Visani, Valentin Dediu, Shelyakova, Tatiana, Russo, Alessandro, Visani, Andrea, Dediu, Valentin Alek, and Marcacci, Maurilio

Subjects
Magnetic force, Bone fixation, Scaffold, medicine.medical_specialty, Materials science, Long bone, Finite Element Analysis, Health Informatics, Rod, law.invention, Intramedullary rod, Fixation (surgical), Magnetics, law, medicine, Humans, Computer Simulation, Orthopedic Procedures, Magnetic application, Fracture treatment, Computer Science Applications1707 Computer Vision and Pattern Recognition, equipment and supplies, Stainless Steel, Finite element method, Internal Fixators, Computer Science Applications, Surgery, medicine.anatomical_structure, Magnet, Orthopedic surgery, Stress, Mechanical, Scaffold fixation, human activities, Biomedical engineering
Abstract

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 magnetic forces.The efficiency of this approach was investigated on the basis of finite element modeling for scaffold application and analytical calculations for diaphyseal fractures. Three different configurations have been analyzed including combinations of small cylindrical permanent magnets or stainless steel rods, inserted rigidly in the bone intramedullary canals and in the scaffold. It was shown that attractive forces as high as 75N can be achieved. While these forces do not reach the strength of mechanical forces in traditional fixators, the employment of magnetic rods is expected to be beneficial by reducing considerably the interface micromotions. It can additionally support magneto-mechanical stimulations as well as enabling a magnetically assisted targeted delivery of drugs and other bio-agents. Display Omitted An innovative magnetic fixation method is proposed for orthopedics.Magnetic rods can be used for long bone and scaffold fixation.Magnetic configurations, compatible with real patient cases, were analyzed.Magnetic fixation forces can achieve values as high as 75N.Magnetic fixation can reduce the interface micromotions and provide bone stimulation.

Published
2014

26. Synthesis and Characterization of a Biocompatible Nanoplatform Based on Silica-Embedded SPIONs Functionalized with Polydopamine.

Author

Romano M, González Gómez MA, Santonicola P, Aloi N, Offer S, Pantzke J, Raccosta S, Longo V, Surpi A, Alacqua S, Zampi G, Dediu VA, Michalke B, Zimmerman R, Manno M, Piñeiro Y, Colombo P, Di Schiavi E, Rivas J, Bergese P, and Di Bucchianico S

Subjects
Animals, Silicon Dioxide pharmacology, Magnetic Iron Oxide Nanoparticles, Indoles pharmacology, Magnetite Nanoparticles toxicity
Abstract

Superparamagnetic iron oxide nanoparticles (SPIONs) have gained increasing interest in nanomedicine, but most of those that have entered the clinical trials have been withdrawn due to toxicity concerns. Therefore, there is an urgent need to design low-risk and biocompatible SPION formulations. In this work, we present an original safe-by-design nanoplatform made of silica nanoparticles loaded with SPIONs and decorated with polydopamine (SPIONs@SiO2-PDA) and the study of its biocompatibility performance by an ad hoc thorough in vitro to in vivo nanotoxicological methodology. The results indicate that the SPIONs@SiO 2 -PDA have excellent colloidal stability in serum-supplemented culture media, even after long-term (24 h) exposure, showing no cytotoxic or genotoxic effects in vitro and ex vivo. Physiological responses, evaluated in vivo using Caenorhabditis elegans as the animal model, showed no impact on fertility and embryonic viability, induction of an oxidative stress response, and a mild impact on animal locomotion. These tests indicate that the synergistic combination of the silica matrix and PDA coating we developed effectively protects the SPIONs, providing enhanced colloidal stability and excellent biocompatibility.

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results