National Institute Of Materials Physics - Romania

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873 articles found

541. Pizeoelectric epitaxial sol-gel Pb(Zr0.52Ti0.48)O-3 film on Si(001)

Authors: Yin, S; Le Rhun, G; Defay, E; Vilquin, B; Niu, G; Robach, Y; Dragoi, C; Trupina, L; Pintilie, L

Published: 2012, 2012 INTERNATIONAL SYMPOSIUM ON APPLICATIONS OF FERROELECTRICS HELD JOINTLY WITH 11TH IEEE ECAPD AND IEEE PFM (ISAF/ECAPD/PFM), DOI:

Epitaxial Pb(Zr0.52Ti0.48)O-3 (PZT) thin film has been successfully integrated on Si(001) substrate by sol-gel method. SrTiO3 (STO) layer deposited on Si by Molecular Beam Epitaxy (MBE) acts as a template layer in this study to avoid the formation of amorphous SiO2, and allows the chemical compatibility for further epitaxial growth. For bottom electrode, SrRuO3 (SRO) layer grown by Pulsed Laser Deposition (PLD) on STO/Si was used. Epitaxial single crystalline growth of PZT film after Rapid Thermal Annealing (RTA) at 650 C was evidenced by X-Ray Diffraction (XRD). The following relationship in the heterostructure was deduced: [110] PZT (001) // [110] SRO (001) // [110] STO (001) // [100] Si (001). A clear piezoelectric response of the film was observed by Piezoresponse Force Microscope (PFM). Moreover, the structural STO quality was proved to have a major impact on the electrical properties of PZT films.

542. ZnO Thin Films Deposited on Textile Material Substrates for Biomedical Applications ZnO Thin Films Deposited on Textiles

Authors: Duta, L; Popescu, AC; Dorcioman, G; Mihailescu, IN; Stan, GE; Zgura, I; Enculescu, I; Dumitrescu, I

Published: 2012, TECHNOLOGICAL INNOVATIONS IN SENSING AND DETECTION OF CHEMICAL, BIOLOGICAL, RADIOLOGICAL, NUCLEAR THREATS AND ECOLOGICAL TERRORISM, 210, DOI: 10.1007/978-94-007-2488-4_20

We report on the coating with ZnO adherent thin films of cotton woven fabrics by Pulsed laser deposition technique in order to obtain innovative textile materials, presenting protective effects against UV radiations and antifungal action.

543. Ba(Zn1/3Ta2/3)O-3 perovskite ceramics doped with Nb5+, Ce4+ or Yb3+

Authors: Busuioc, C; Jinga, SI; Stoleriu, S; Nedelcu, L; Andronescu, E

Published: MAR-APR 2012, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, 14, 244, DOI:

Ba(Zn1/3Ta2/3)O-3 (BZT) perovskite material has stimulated a large interest due to its excellent dielectric properties in microwave frequency range, enabling the miniaturization of communications devices. In this work, BZT ceramics were prepared by the conventional solid-state reaction method, being doped with Nb5+, Ce4+ or Yb3+. BZT resonators were compositional, structural, morphological and electrical characterized. The influence of the dopants and sintering temperature on the microwave dielectric properties of BZT samples was investigated. The resonator doped with 0.5 mol% Nb2O5 and sintered at 1600 degrees C / 2 h exhibits the best dielectric behaviour: e(r) similar to 25.9 and Qxf similar to 159 THz.

544. Ba(X1/3Ta2/3)O-3 COMPLEX PEROVSKITES FOR MICROWAVE AND MILLIMETER-WAVE APPLICATIONS

Authors: Nedelcu, L; Busuioc, C; Banciu, MG; Ramer, R

Published: 2012, 2012 INTERNATIONAL SEMICONDUCTOR CONFERENCE (CAS), VOLS 1 AND 2, 2, 306, DOI:

Ba(X1/3Ta2/3)O-3 (X = Zn, Mg) perovskites were prepared by using the solid state reaction method. X-ray diffraction and scanning electron microscopy were employed for structural and morphological characterization of Ba(X1/3Ta2/3)O-3 samples. The dielectric constant of the resonators was 28 for Ba(Zn1/3Ta2/3)O-3 and 24 for Ba(Mg1/3Ta2/3)O-3. A strong influence of the cation ordering on the dielectric loss has been found. The achieved values of Q x f product, ranging from 100 to 200 THz, make Ba(X1/3Ta2/3)O-3 dielectric resonators attractive for microwave and millimetre-wave applications.

545. CORTICAL BONE AS RESOURCE FOR PRODUCING BIOMIMETIC MATERIALS FOR CLINICAL USE

Authors: Miculescu, F; Stan, GE; Ciocan, LT; Miculescu, M; Berbecaru, A; Antoniac, I

Published: OCT-DEC 2012, DIGEST JOURNAL OF NANOMATERIALS AND BIOSTRUCTURES, 7, 1677, DOI:

The search of new alternative materials for bone reconstruction is a major objective in biomaterials engineering and reconstructive medicine. In this study the compact bone derived materials are proposed, their structure and composition being modified by thermal treatments performed in 200-1200 degrees C range, using 200 degrees C temperature steps. The monitoring of the bone modifications under heat-treatment was carried out using thermal analysis (TGA-DSC), microstructural (SEM), compositional (EDS) and structural (FTIR, XRD) methods. Tailoring the bone material's morphological, chemical and structural properties by heat-treatments, expressed by the HA/beta-TCP compositional ratio, degree of crystallinity and porosity control, could lead to the obtaining of good quality bone substitute materials suitable for the bone regeneration of large osseous defects.

546. Cylindrical resonator antenna manufactured with Barium Neodymium Titanate

Authors: Nicolaescu, I; Avadanei, OG; Nedelcu, L; Toacsan, MI; Banciu, MG; Andrei, I; Balmus, SB

Published: NOV-DEC 2012, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, 14, 1010, DOI:

The rapid evolution of GPS, mobile and wireless communication systems in the last years is based, substantially, on ceramic based dielectrics with effect on miniaturization of components (antennas, filters, oscillators), cost and temperature stability. The development of high dielectric constant materials was critical for the dimensions reduction of the equipment but also for their performance improvements. These materials have high dielectric constant, epsilon(r), between 20 and 90; low losses in microwave and millimetre wave domain and a low variation of dielectric constant with the temperature. The paper describes a high dielectric constant material, Barium Neodymium Titanate - (Ba,Pb)Nd2Ti4O12 (BNT), and presents some results obtained by using this ceramic based material to manufacture a dielectric resonator antenna.

547. High quality amorphous indium zinc oxide thin films synthesized by pulsed laser deposition

Authors: Socol, G; Craciun, D; Mihailescu, IN; Stefan, N; Besleaga, C; Ion, L; Antohe, S; Kim, KW; Norton, D; Pearton, SJ; Galca, AC; Craciun, V

Published: DEC 1 2011, THIN SOLID FILMS, 520, 1277, DOI: 10.1016/j.tsf.2011.04.196

Indium zinc oxide films were grown from targets with two different In atomic concentration [In/(In+Zn)] of 40% and 80% by the pulsed laser deposition technique on glass substrates from room temperature up to 100 degrees C. X-ray diffraction and reflectometry investigations showed that films were amorphous and dense. Thin films (thickness<100 nm) exhibited higher optical transmittance and resistivities than thick films (thickness>1000 nm), probably caused by a significant decrease of oxygen vacancies due to atmosphere exposure. Films deposited from the In rich target under an oxygen pressure of 1 Pa exhibited optical transmittance higher than 85%, resistivities around 5-7x10(-4) Omega cm and mobilities in the 47-54 cm(2)/V s range. (C) 2011 Elsevier B. V. All rights reserved.

548. Silicon detectors for the sLHC

Authors: Affolder, A; Aleev, A; Allport, PP; Andricek, L; Artuso, M; Balbuena, JP; Barabash, L; Barber, T; Barcz, A; Bassignana, D; Bates, R; Battaglia, M; Beimforde, M; Bemardini, J; Betancourt, C; Bilei, GM; Bisello, D; Blue, A; Bohm, J; Bolla, G; Borgia, A; Borrello, L; Bortoletto, D; Boscardin, M; Bosma, MJ; Bowcock, TJV; Breindl, M; Broz, J; Bruzzi, M; Brzozowski, A; Buhmann, P; Buttar, C; Campabadal, F; Candelori, A; Casse, G; Charron, S; Chren, D; Cihangir, S; Cindro, V; Collins, P; Gil, EC; Costinoaia, CA; Creanza, D; Cristobal, C; Dalla Betta, GF; de Boer, W; De Palma, M; Demina, R; Dierlamm, A; Diez, S; Dobos, D; Doherty, F; Kittelmann, ID; Dolezal, Z; Dolgolenko, A; Dragoi, C; Driewer, A; Dutta, S; Eckstein, D; Eklund, L; Eremin, I; Eremin, V; Erfle, J; Fadeeva, N; Fahrer, M; Fiori, F; Fleta, C; Focardi, E; Forshaw, D; Fretwurst, E; Frey, M; Bates, AG; Gallrapp, C; Garcia, C; Gaubas, E; Genest, MH; Giolo, K; Glaser, M; Goessling, C; Golubev, A; Gorelov, I; Gregoire, G; Gregori, P; Grigoriev, E; Grillo, AA; Grinstein, S; Groza, A; Guskov, J; Hansen, TE; Harkonen, J; Hartjes, FG; Hartmann, F; Hoeferkamp, M; Horisberger, R; Houdayer, A; Hynds, D; Ilyashenko, I; Junkes, A; Kadys, A; Kaminski, P; Karpenko, A; Kaska, K; Kazuchits, N; Kazukauskas, V; Kharchuk, A; Khivrich, V; Kierstead, J; Klanner, R; Klingenberg, R; Kodys, P; Koffeman, E; Kohler, M; Kohout, Z; Korjenevski, S; Korolkov, I; Kozlowski, R; Kozubal, M; Kramberger, G; Kuhn, S; Kuleshov, S; Kuznetsov, A; Kwan, S; La Rosa, A; Lacasta, C; Lange, J; Lassila-Perini, K; Lastovetsky, V; Lazanu, I; Lazanu, S; Lebel, C; Lefeuvre, G; Lemaitre, V; Leroy, C; Li, Z; Lindstrom, G; Litovchenko, A; Litovchenko, P; Lozano, M; Luczynski, Z; Luukka, P; Macchiolo, A; Macraighne, A; Maenpaa, T; Makarenko, LF; Mandic, I; Maneuski, D; Manna, N; Marco, R; Garcia, SII; Marunko, S; Masek, P; Mathieson, K; Matysek, M; Mekki, J; Messineo, A; Metcalfe, J; Mikestikova, M; Mikuz, M; Militaru, O; Minano, M; Miyamoto, J; Moll, M; Monokhov, E; Mori, R; Moser, HG; Muenstermann, D; Sanchez, FJM; Naletko, A; Nisius, R; Oshea, V; Pacifico, N; Pantano, D; Parkes, C; Parzefall, U; Passeri, D; Pawlowski, M; Pellegrini, G; Pernegger, H; Petasecca, M; Piemonte, C; Pignatel, GU; Pintilie, I; Pintilie, L; Piotrzkowski, K; Placekett, R; Pohlsen, T; Polivtsev, L; Popule, J; Pospisil, S; Preiss, J; Radicci, V; Radu, R; Raf, JM; Rando, R; Richter, R; Roeder, R; Roger, R; Rogozhkin, S; Rohe, T; Ronchin, S; Rott, C; Roy, A; Rummler, A; Ruzin, A; Sadrozinski, HFW; Sakalauskas, S; Samadashvili, N; Scaringella, M; Schumm, B; Seidel, S; Seiden, A; Shipsey, I; Sibille, J; Sicho, P; Slavicek, T; Solar, M; Soldevila-Serrano, U; Son, S; Sopko, V; Sopko, B; Spencer, N; Spiegel, L; Srivastava, A; Steinbrueck, G; Stewart, G; Stolze, D; Storasta, J; Surma, B; Svensson, BG; Tan, P; Tomasek, M; Toms, K; Tsiskaridze, S; Tsvetkov, A; Tuboltsev, Y; Tuominen, E; Tuovinen, E; Tuuva, T; Tylchin, M; Uebersee, H; Ullan, M; Vaitkus, JV; van Beuzekom, M; Verbitskaya, E; Alvarez, IV; Visser, J; Vossebeld, J; Vrba, V; Walz, M; Weigell, P; Wiik, L; Wilhelm, I; Wunstorf, R; Zaluzhny, A; Zavrtanik, M; Zelazko, J; Zen, M; Zhukov, V; Zontar, D; Zorzi, N

Published: DEC 1 2011, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 658, 16, DOI: 10.1016/j.nima.2011.04.045

In current particle physics experiments, silicon strip detectors are widely used as part of the inner tracking layers. A foreseeable large-scale application for such detectors consists of the luminosity upgrade of the Large Hadron Collider (LHC), the super-LHC or sLHC, where silicon detectors with extreme radiation hardness are required. The mission statement of the CERN RD50 Collaboration is the development of radiation-hard semiconductor devices for very high luminosity colliders. As a consequence, the aim of the R&D programme presented in this article is to develop silicon particle detectors able to operate at sLHC conditions. Research has progressed in different areas, such as defect characterisation, defect engineering and full detector systems. Recent results from these areas will be presented. This includes in particular an improved understanding of the macroscopic changes of the effective doping concentration based on identification of the individual microscopic defects, results from irradiation with a mix of different particle types as expected for the sLHC, and the observation of charge multiplication effects in heavily irradiated detectors at very high bias voltages. (C) 2011 Elsevier B.V. All rights reserved.

549. Highly adherent bioactive glass thin films synthetized by magnetron sputtering at low temperature

Authors: Stan, GE; Pasuk, I; Husanu, MA; Enculescu, I; Pina, S; Lemos, AF; Tulyaganov, DU; El Mabrouk, K; Ferreira, JMF

Published: DEC 2011, JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 22, 2710, DOI: 10.1007/s10856-011-4441-1

Thin (380-510 nm) films of a low silica content bioglass with MgO, B2O3, and CaF2 as additives were deposited at low-temperature (150A degrees C) by radio-frequency magnetron sputtering onto titanium substrates. The influence of sputtering conditions on morphology, structure, composition, bonding strength and in vitro bioactivity of sputtered bioglass films was investigated. Excellent pull-out adherence (similar to 73 MPa) was obtained when using a 0.3 Pa argon sputtering pressure (BG-a). The adherence declined (similar to 46 MPa) upon increasing the working pressure to 0.4 Pa (BG-b) or when using a reactive gas mixture (similar to 50 MPa). The SBF tests clearly demonstrated strong biomineralization features for all bioglass sputtered films. The biomineralization rate increased from BG-a to BG-b, and yet more for BG-c. A well-crystallized calcium hydrogen phosphate-like phase was observed after 3 and 15 days of immersion in SBF in all bioglass layers, which transformed monotonously into hydroxyapatite under prolonged SBF immersion. Alkali and alkali-earth salts (NaCl, KCl and CaCO3) were also found at the surface of samples soaked in SBF for 30 days. The study indicated that features such as composition, structure, adherence and bioactivity of bioglass films can be tailored simply by altering the magnetron sputtering working conditions, proving that this less explored technique is a promising alternative for preparing implant-type coatings.

550. Study of X-ray radiation damage in silicon sensors

Authors: Zhang, J; Fretwurst, E; Klanner, R; Perrey, H; Pintilie, I; Poehlsen, T; Schwandt, J

Published: NOV 2011, JOURNAL OF INSTRUMENTATION, 6, DOI: 10.1088/1748-0221/6/11/C11013

The European X-ray Free Electron Laser (XFEL) will deliver 30,000 fully coherent, high brilliance X-ray pulses per second each with a duration below 100 fs. This will allow the recording of diffraction patterns of single complex molecules and the study of ultra-fast processes. Silicon pixel sensors will be used to record the diffraction images. In 3 years of operation the sensors will be exposed to doses of up to 1 GGy of 12 keV X-rays. At this X-ray energy no bulk damage in silicon is expected. However fixed oxide charges in the insulating layer covering the silicon and interface traps at the Si-SiO(2) interface will be introduced by the irradiation and build up over time. We have investigated the microscopic defects in test structures and the macroscopic electrical properties of segmented detectors as a function of the X-ray dose. From the test structures we determine the oxide charge density and the densities of interface traps as a function of dose. We find that both saturate (and even decrease) for doses between 10 and 100 MGy. For segmented sensors the defects introduced by the X-rays increase the full depletion voltage, the surface leakage current and the inter-pixel capacitance. We observe that an electron accumulation layer forms at the Si-SiO(2) interface. Its width increases with dose and decreases with applied bias voltage. Using TCAD simulations with the dose dependent parameters obtained from the test structures, we are able to reproduce the observed results. This allows us to optimize the sensor design for the XFEL requirements. In addition the Si-SiO(2) interface region has been studied with time resolved signals induced by sub-nanosecond 660 nm laser light, which has a penetration of about 3 m m in silicon. Depending on the biasing history, humidity and irradiation dose, losses of either electrons or holes or no charge losses are observed. The relevance of these results for the sensor stability and performance is under investigation.