1. Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisationDarja Lisjak, Iztok Arčon, Matic Poberžnik, Gabriela Herrero‑Saboya, Ali Tufani, Andraž Mavrič, Matjaž Valant, Patricija Hribar Boštjančič, Alenka Mertelj, Darko Makovec, Layla Martin‑Samos, 2023, izvirni znanstveni članek Opis: Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1–4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe–phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.
Ključne besede: barium hexaferrite, Fe XANES, EXAFS, magnetic nanoparticles
Objavljeno v RUNG: 06.07.2023; Ogledov: 2203; Prenosov: 7
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2. O[sub]2 loaded germanosilicate optical fibers : experimental in situ investigation and ab initio simulation study of GLPC evolution under irradiationImène Reghioua, Luigi Giacomazzi, Antonino Alessi, Blaž Winkler, Layla Martin-Samos, Sylvain Girard, Diego Di Francesca, Mattia Fanetti, Nicolas Richard, Matjaž Valant, 2022, izvirni znanstveni članek Ključne besede: optical fiber, O2 loading, point defects
Objavljeno v RUNG: 25.04.2022; Ogledov: 2334; Prenosov: 30
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3. Unravelling the P[sub]3 centers origin in alkali phosphate glassesLuigi Giacomazzi, Nikita S. Shcheblanov, Layla Martin-Samos, Matjaž Valant, Nadege Ollier, Nicolas Richard, 2021, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: EPR, DFT, NaPO3, LiPO3, alkali phosphate glasses, point defects
Objavljeno v RUNG: 29.09.2021; Ogledov: 2511; Prenosov: 9
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4. Unravelling the P[sub]3 centers origin in alkali phosphate glassesLuigi Giacomazzi, Nikita S. Shcheblanov, Layla Martin-Samos, Matjaž Valant, Nadege Ollier, Nicolas Richard, 2021, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: EPR, DFT, NaPO3, LiPO3, alkali phosphate glasses, point defects
Objavljeno v RUNG: 29.09.2021; Ogledov: 2573; Prenosov: 0
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5. Paramagnetic intrinsic point defects in alkali phosphate glasses : unraveling the P[sub]3 center origin and local environment effectsLuigi Giacomazzi, Nikita S. Shcheblanov, Layla Martin-Samos, Mikhail E. Povarnitsyn, Shinji Kohara, Matjaž Valant, Nicolas Richard, Nadege Ollier, 2021, izvirni znanstveni članek Ključne besede: oxygen, electron paramagnetic resonance spectroscopy, phosphates, amorphous materials, defects
Objavljeno v RUNG: 04.05.2021; Ogledov: 3559; Prenosov: 0
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6. Ultraviolet absorption and transient photocurrent spectroscopy in organic thin layers as evidence of super atomic molecular orbitals in corannuleneNadiia Pastukhova, Layla Martin-Samos, Laura Zoppi, Egon Pavlica, Jinta Mathew, Gvido Bratina, J. S. Siegel, Kim K. Baldridge, 2018, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: photocurrent spectroscopy, organic thin layers, atomic molecular orbitals
Objavljeno v RUNG: 03.11.2020; Ogledov: 3403; Prenosov: 75
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7. Vers une connaissance microscopique de la structure de verres de phosphate P2O5Nicolas Richard, Luigi Giacomazzi, Nikita S. Shcheblanov, Layla Martin-Samos, Nadege Ollier, 2020, poljudni članek Opis: Les propriétés d’amplification de la lumière des ions terres rares permettent en les incluant comme dopants dans le cœur des fibres optiques d’obtenir des sources laser et des amplificateurs de lumière compacts. Pour réduire la tendance à l’agrégation des terres rares qui diminuent leurs propriétés amplificatrices, le phosphore est employé comme co-dopant dans ces fibres. Cet article montre comment les méthodes de simulation à l’échelle atomique
peuvent aider a' l'optimisation de ce co-dopage en contribuant a' une meilleure comprehension de la structure des verres phosphates
[1] et des défauts qui leur sont liés [2]. Au CEA-DAM, ces resultats serviront aussi dans le cadre d'etudes sur le developpement de fibres optiques pour des mesures de dosimetrie radiative.
Ključne besede: glasses, P2O5, point defects, ab-initio
Objavljeno v RUNG: 18.09.2020; Ogledov: 3941; Prenosov: 0
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9. v-P2O5 micro-clustering in P-doped silica studied by a first-principles Raman investigationLuigi Giacomazzi, Layla Martin-Samos, Antonino Alessi, A. Boukenter, Youcef Ouerdane, Sylvain Girard, Nicolas Richard, Matjaž Valant, Stefano de Gironcoli, 2019, izvirni znanstveni članek Ključne besede: silica, POHC, optical fibers, Raman, EPR
Objavljeno v RUNG: 10.05.2019; Ogledov: 4107; Prenosov: 0
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10. Overview of radiation induced point defects in silica-based optical fibersSylvain Girard, Antonino Alessi, Vincenzo De Michele, Youcef Ouerdane, A. Boukenter, Adriana Morana, Nicolas Richard, Philippe Paillet, Marco Cannas, Simonpietro Agnello, Imène Reghioua, Blaz Winkler, Layla Martin-Samos, Luigi Giacomazzi, Diego Di Francesca, Thierry Robin, 2019, pregledni znanstveni članek Ključne besede: optical fibers, point defects, radiation-induced attenuation, GLPC, NBOHC, STH, ODC, P-doping, Ge-doping, Al-doping
Objavljeno v RUNG: 09.05.2019; Ogledov: 4025; Prenosov: 0
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