Navegação Eventos - Resumos por autor "VANTOMME, ANDRE"

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  • IPEN-DOC 23311

    PEREIRA, LUCIANO F. ; MESTNIK-FILHO, JOSE ; CARBONARI, ARTUR ; CAVALCANTE, FABIO ; LEITE-NETO, OSMAR . First-principles calculations of the magnetic hyperfine field at Cd sites in RECd (RE = rare-earth element). In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Binary magnetic compounds based on rare-earth (RE) elements of the type REX, where X is a transition metal, with the simplest stoichiometry and crystalline cubic structure, are isostructural systems with different RE constituents, which differ only slightly in the crystallographic properties, but strongly in the magnetic properties. They thus offer excellent conditions for the separation of the magnetic from other solid-state parameters and permit the magnetism studies. However, in most RE compounds and, particularly when X=Cd, details of the magnetic structure at an atomic scale are not available mainly because is not possible to use neutron diffraction to investigate them. In this paper, the magnetic hyperfine field (mhf) at Cd sites in RECd compounds was studied by first-principles calculation. These compounds crystalizes in the CsCl prototype cubic structure (Pm-3m space-group) and order ferromagnetically below the Curie temperature with exception of PrCd, which presents antiferromagnetism. Recently, it was observed an unexpected transition in the mhf at 111Cd in DyCd below 40 K, when mhf vanishes [1]. We have used the density functional theory framework with full potential Augmented Planes Waves plus local orbitals (APW+lo) method embodied in the WIEN2k code to simulate electronic structures of the ferromagnetic and antiferromagnetic crystal cells in these compounds. For the exchange-correlation effects we chose local density approximation. The mhf at Cd sites and the formation energy were calculated for each compound as well as the density of states were obtained. Results of mhf are in very good agreement (less than 10%) with the experimental values previously reported [1]. Interestingly, for DyCd the energy for the formation of the antiferromagnetic ordering with (π, π, 0) structure is smaller than that for the ferromagnetic and others possible antiferromagnetic phases. As far as we know, it is the first time that such an excellent agreement between the calculated and experimental mhf at Cd sites is observed. Moreover, this results is even more important because the calculations were fully variational without the use of the Hubbard model which takes into account the on-site correlation of 4f electrons.

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  • IPEN-DOC 23308

    KRYLOV, VASILY I. ; BOSCH-SANTOS, BRIANNA ; CABRERA-PASCA, GABRIEL A. ; CARBONARI, ARTUR W. . Huge negative magnetic hyperfine fields for 111Cd probe nuclei in the Fe3X (X=C, Ge, and Ga) compounds with specific properties. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: In recent years, Fe3X (X = C, Ga, and Ge) alloys are actively investigated experimental and theoretical methods due to their potential practical use as invar, magnetostrictive materials, and multi-layered ferromagnetic film [1-3]. The Fe3C alloy was studied by nuclear resonant scattering on 57Fe and by x-ray emission spectroscopy at high pressure up to 50 GPa because this substance could be the major Earth’s inner core component [4, 5]. In this work we found huge negative HFs reaching a magnitude of Bhf = -46T on 111Cd probe nuclei in ferromagnetic Fe3X (X = C, Ga, and Ge) alloys by perturbed γ-γ angular correlation (PAC) spectroscopy. These values are the highest known HFs on 111Cd nuclei in metallic magnets. It was established that in Fe3C crystallizing in the orthorhombic DO11 structure (Pnma space group) 111Cd probes are placed in Feg sites with 11Fe atoms as nearest neighbours (n.n.). For Feg positions, the n.n. arrangement is similar to normal hexagonal close packing. The HF value for 111Cd atoms in Fe3C is equal to Bhf = -38.0(1) T at 77K. In tetragonal DO3 crystal structure of Fe3Ga 111Cd probes are placed in both Ga sites (12 n.n. Fe) and in FeII (8n.n.Fe). The HFs for 111Cd atoms in Fe3Ga are equal to Bhf = -39.8(1) T and Bhf = -24.2(3) T at 77K for Ga and FeII sites of 111Cd localization. In hexagonal DO19 crystal structure of Fe3Ge 111Cd probes are placed in Ge sites (12 n.n.). The HF value for 111Cd probes in Fe3Ge is equal to Bhf = -46.0(1) T at 40K. There are no any anomalies of the Bhf (T) on 111Cd nuclei in the spin reorientation region of Fe3Ge. The results of this work are analyzed with the previously obtained HF’s values on 111Cd nuclei in 3d metals and their alloys including Heusler alloys.

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  • IPEN-DOC 23310

    ANDRE-FILHO, J.; COAQUIRA, J.A.H.; MESTNIK-FILHO, J. ; CARBONARI, A.W. ; NAGAMINE, L.C.C.M.. Hydrogen absorption effects on the physical properties of ball-milled LaNiSn intermetallic compounds. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: A polycrystalline samples were prepared by arc melting high-purity elements under argon atmosphere. The samples were re-melted several times to ensure homogeneity. After arc-melting, the samples were annealed in vacuum at 800°C for 28h. After that, some samples were milled using a Ball milling technique. The hydrogenation was carried out by the Sievert’s method using a high purity hydrogen gas. X-ray diffraction (XRD) measurements indicate the formation of the TiNiSi-type orthorhombic structure with space group Pnma for the unmilled sample and its hydride. The milled samples show broad peaks and poor crystallinity hindering the analysis of the structural properties. One sample was milled with 10wt% of graphite. The analysis of the graphite-milled sample reveals that graphite preserves the structural properties (the sample shows better crystalline quality) and acts as a catalyst for the absorption of hydrogen. The analyses of the XRD patterns show that the structural parameters are modified after the hydrogenation. The transmission electron microscope images corroborate the XRD data. Mössbauer spectra (297K) of the unmilled LaNiSn show the presence of only one doublet inconsistency with the one symmetry site of Sn atoms in the TiNiSn-type structure. Moreover, spectra of the milled samples are better reproduced by considering three doublets. Those components were associated with Sn atoms occupying regular sites (D1), Sn atoms substituting Ni atoms (D2) and Sn atoms of some spurious phase or Sn atoms localized in the interface region of the grains (D3). The spectral area of the D1 component decreases at expenses of the other two components. However, the isomeric shift (IS) of D1 and D2 shows a constant value as the milling time is increased. The IS of the third doublet shows some fluctuating behavior likely related to its small spectral area. The quadrupole splitting (QS) of D2 component shows larger value than that of the D1 component and both show clear increasing tendency as the milling time is increased. After the hydrogenation, the IS shows an increase related to the samples before hydrogenation. However, the IS of the D1 and D2 components do not undergo a drastic change in value with the milling time. The value of the QS of D1 and D2 components show an increase with the milling time. This result has been assigned to the indirect interaction between Sn and H atoms which causes an asymmetric electron distribution around the Sn atoms.

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  • IPEN-DOC 23305

    DOMIENIKAN, CLAUDIO ; BOSCH-SANTOS, BRIANNA ; PASCA, GABRIEL A.C. ; SAXENA, RAJENDRA ; CARBONARI, ARTUR . Hyperfine field at La in the intermetallic compound LaMnSi2 measured by PAC using 140Ce nuclear probe. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Magnetic hyperfine field has been measured in the orthorhombic intermetallic compound LaMnSi2 with PAC spectroscopy using radioactive 140La-140Ce nuclear probes. Magnetization measurement was also carried out in this compound with MPSM-SQUID magnetometer. The LaMnSi2 sample was prepared by melting pure metallic components in stoichiometric proportions in an arc furnace under argon atmosphere. After melting, the sample was annealed at 1000 o C for 60h under helium atmosphere and then quenched in to water. X-ray analysis confirmed the sample to be in a single phase with correct crystal structure expected for LaMnSi2. The radioactive nuclei, 140La (T1/2 = 40h) were produced by direct irradiation of the sample with neutrons in the IEA-R1 nuclear research reactor at IPEN with a flux of ~1013 ncm-2s-1 for about 3-4 min. The irradiated sample was annealed at 1000 o C under helium atmosphere for 24 hours before starting the PAC measurement in order to minimize the effects of eventual radiation damage by fast neutrons during irradiation as well as to allow the decay of the short lived 56Mn (T1/2 = 2.6h) activity also produced in the sample. The PAC measurements were carried out with a six BaF2 detector spectrometer at several temperatures between 10 K and 400 K. The results showed well defined magnetic dipole interaction at all temperatures. Temperature dependence of the hyperfine field, Bhf was found to be anomalous. The magnetization measurement however, showed no anomaly. Therefore, the anomalous behavior of Bhf may be attributed to the interaction where 1f electron of the dilute Ce atom is spin polarized by the magnetic field from Mn sublattice and contributes to the effective hyperfine field. The ferromagnetic transition temperature (TC) of LaMnSi2 was determined to be 400(1) K confirming by magnetic measurement and the earlier results.

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  • IPEN-DOC 23301

    SILVA, ERIC B. da ; CORREIA, JOAO G.; ZOGHBY, MICHEL; GAHL, JOHN; SCHELL, JULIANA; MATOS, IZABELA T. de ; RIBEIRO JUNIOR, IBERE S. ; CARBONARI, ARTUR W. ; HUBLER, GRAHAM K.; VIOLANTE, VITTORIO; THIOYE, MOUSTAPHA; HE, JINGHAO. Hyperfine interactions in Pd foils during D/H electrochemical loading. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: The Fleischmann and Pons Effect (FPE) is the appearance of anomalous excess heat during electrolytic loading of hydrogen in metal. Although observed well above measurement uncertainties [1] this effect still remains unexplained. Unlike previous studies where hydrogen (H) was pre-loaded before Time Differential Perturbed Angular Correlations (TDPAC) [2,3] was performed, this present work probes, at the nanoscopic scale, palladium (Pd) samples during H and deuterium (D) loading in 0.1M LiOH or LiOD electrolyte. Radioactive 181Hf (181Ta) was implanted at 80 keV (HISKP-Bonn) and experiments were performed at the ISOLDE-CERN SSP laboratories after vacuum annealing to recover implantation defects. An almost “flat” unperturbed PAC – R(t) spectrum was observed, as expected for Hf/Ta atoms at cubic Pd sites with no remaining point defects in their vicinity. Upon D loading the “flat” unperturbed R(t) spectrum changes to a characteristic Gaussian-like EFG distribution, centered near zero EFG, due to the random distribution of D atoms inside the Pd lattice. With increasing D concentration, the central value of the distribution becomes nonzero, thus revealing that the Pd crystalline structure is relaxed from cubic, consistent with the phase diagram for Pd hydrides. The data also shows that, while being an impurity in the system under study, the Hf/Ta atoms do not trap nor significantly interfere with the H/D atoms in the Pd lattice that would bias the present studies. Thus, further experiments aimed at studying the FPE under external excitations are envisaged.

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  • IPEN-DOC 23312

    CAVALCANTE, FABIO H. de M.; SALES, TATIANE S.N. ; DAY, TRAVIS; LEITE NETO, OSMAR F.S. ; PEREIRA, LUCIANO F.D. ; SAXENA, RAJENDRA N. ; CARBONARI, ARTUR W. ; MENONI, CARMEN. Influence of oxygen atmosphere in the annealing of HfO2 thin films studied by perturbed angular correlation spectroscopy. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: The thin films of HfO2 have been grown by dual ion beam sputtering (DIBS) on transparent quartz substrates (grade silica) and silicon wafers. The major benefits of the DIBS process are the increased packing density of the deposited films which makes them more bulk-like, the improved adhesion resulting from the mixing of the materials at the interfaces between each layer, and the reduction of the high tensile stress in the layers. Deposition conditions were adjusted to obtain polycrystalline as well as amorphous films. In this study the time differential perturbed angular correlation (PAC) spectroscopy was used to study the influence of oxygen atmosphere in the annealing of the HfO2 thin film. The PAC method is based on the hyperfine interaction of nuclear moments of the probe with extra nuclear magnetic fields or electric field gradients (EFGs). In the case of quadrupolar interaction, the experimental measurement gives the quadrupolar frequency νQ with respective distribution δ as well as the asymmetry parameter η of EFG. The presence of the 180Hf isotope in natural hafnium allows the possibility of using 181Ta as a probe nucleus formed by irradiating the samples with neutrons via 180Hf(n,γ)181Hf reaction. After irradiation, samples were annealed in oxygen atmosphere at different temperatures. The γ-γ PAC measurements were then carried out using a standard set up with four conical BaF2 detector scintillators with a time resolution of 0.6 ns (FWHM). Results show a structural transition from monoclinic to tetragonal in the annealed samples.

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  • IPEN-DOC 23307

    SILVA, ANDREIA ; AMARAL, ANTONIO ; LAPOLLI, ANDRE ; SAXENA, RAJENDRA ; CARBONARI, ARTUR . Investigation of hyperfine interactions in immunoglobulin G with perturbed angular correlation spectroscopy using 111Cd. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Hyperfine interaction parameters have been used to investigate physical properties of biomolecules from different isotypes of immunoglobulins G (IgG1, IgG2a and IgG2b). Immunoglobulin IgG1 induces a pattern of response type Th2 that corresponds to an allergic immunological response, whereas immunoglobulin IgG2 induces a pattern of response Th1 that corresponds to a cellular immunological response, suited for response against parasites. Hyperfine interactions were measured by perturbed gamma-gamma angular correlation (PAC) spectroscopy using 111In(111Cd) and 111mCd(111Cd) as probe nuclei. The measurements were carried out for both the complete and fragmented molecules at 295 K and 77 K, and both static as well as dynamic interactions were observed. Results of both measurements were used to calculate the rotational correlation time for each studied molecule. The complete and fragmented molecules showed different dynamic interactions. It was therefore conclude that the PAC technique is quite adequate for differentiating between the isotypes of immunoglobulins as well as their dynamic behavior if adequate nuclear probe is utilized with rigorous control of measuring conditions. The hyperfine parameters obtained are related to the physical properties of each molecule in an attempt to understand the difference in their biological function.

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  • IPEN-DOC 23306

    SALES, TATIANE ; CAVALCANTE, FABIO ; CABRERA-PASCA, GABRIEL ; PEREIRA, LUCIANO F. ; SAXENA, RAJENDRA ; CARBONARI, ARTUR . Investigation of Rare Earth (RE = La, Dy, and Er) doping of HfO2 by perturbed angular correlation spectroscopy. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: The hyperfine interactions at 181Hf(181Ta) probe nuclei in HfO2 samples doped with 5% rare-earth (RE = La, Dy, and Er) elements were measured by perturbed angular correlation (PAC) spectroscopy. Hafnium dioxide has been extensively studied as a potential alternative to silicon dioxide as dielectric gate material in the silicon based complementary-metal-oxide-semiconductors (CMOS) technology due to its high dielectric constant and relatively high thermal stability with respect to silicon. The addition of RE to HfO2 can suppress oxygen vacancies and promote a change in the crystal structure increasing the dielectric permitivity. Samples were prepared using the sol-gel chemical method, starting from very pure metals. The resulting powder of each sample was annealed in air at 550 o C for 12 h. The crystal structures of samples were checked by X-ray diffraction. Result revealed only a single phase corresponding to the monoclinic phase P 21/C of HfO2 for all samples. PAC spectra measured at room temperature were fitted with two electric quadrupole interactions with different environments for all samples including a pure HfO2. The major components (70-75%) were characterized by quadrupole frequencies 𝜈𝑄 ∼ 790 MHz with a distribution around 6% and asymmetry parameter 𝜂 = 0.34 for Dy- and Er-doped samples. La-doped sample showed a slightly lower frequency (𝜈𝑄 = 727 MHz) with larger asymmetry parameter (𝜂 = 0.43) for the major component. The major components are ascribed to probe nuclei at regular monoclinic sites of HfO2. The quadrupole frequency 𝜈𝑄 and asymmetry parameter 𝜂 for Dy- and Er-doped samples agree well with those values reported in the literature [1]. The minor components were characterized by 𝜈𝑄 ∼ 760 MHz with a distribution around 8% and asymmetry parameter 𝜂 = 0.75 for Dy- and Er-doped samples and 𝜈𝑄 = 783 MHz and 𝜂 = 0.61 for La-doped HfO2. These values are quite different from those reported for pure sample [1], assigned to probe nuclei near defects, and probably they are due to probe nuclei close to RE dopants, which reduce the presence of defects.

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  • IPEN-DOC 23333

    SCHELL, JULIANA; CORREIA, JOAO G.M.; DEICHER, MANFRED; LUPASCU, DORU C.; VIANDEN, REINER; BARBOSA, MARCELO; CARBONARI, ARTUR . Studying after effects by gamma-gamma and electron-gamma perturbed angular correlations. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Using electron-gamma perturbed angular correlations (PAC) experiments working side-by-side with gamma-gamma PAC on the same isomeric transitions, besides structural properties, additional information can be unambiguously obtained by following the electronic recombination at the atomic shells and the neighbor atoms after the emission of the conversion electron from the probe nuclei K, L, or M atomic shells. Such experiments can be envisaged, as well, to clear out gamma-gamma PAC experiments where the probing state is fed by electron capture decay. There, one K, L, M orbital electron is absorbed by a proton creating a hole when the atomic number changes from Z to Z-1. This causes a severe electronic rearrangement of the atomic shells accompanied by the emission of x-rays and Auger electrons. The atom is left in a highly ionized state and the recombination time – fast or slow – depending on the availability and mobility of host electrons determines if a transient effect is observed within the lifetime of the nuclear state used for PAC. This is the so called “after effect”, that if properly understood, can further contribute to learn about the interaction of the impurity probe with the host, eventually observing ionized states and determining electron mobility [1]. Illustrating this problematic we present and discuss in this work the study of TiO2 doping [2] using different PAC isotopes (111In/111Cd, 181Hf/181Ta, 111mCd/111Cd, 117Cd/117In).

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  • IPEN-DOC 23309

    KRYLOV, V.I. ; BOSCH-SANTOS, B. ; CABRERA-PASCA, G.A. ; CARBONARI, A.W. ; SAXENA, R.N. ; MESTNIK-FILHO, J. . Temperature anomalies of the hyperfine magnetic fields on 111Cd probe nuclei in ferro- and antiferromagnetic phases of the ordered FeRh alloys. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: FeRh ordered alloy crystallizes in the bcc B2 structure [1], presents first order phase transition from antiferromagnetic (AF) ordering at low temperature to ferromagnetic (F) state above 350 K [2], and shows significant magnetocaloric effect near RT [3]. Recently, FeRh alloy has also been considered as an interesting material for spintronics applications [4]. In the AF state, FeRh has compensated AFII-type magnetic structure with μFe=3.3 μB and μRh=0. In the F state of FeRh both Fe and Rh atoms have magnetic moments of μFe=3.2 μB and μRh=0.9 μB, respectively [5]. The Fe – Rh compounds were studied by Mössbauer spectroscopy (MS) on 57Fe [6, 7] and 119Sn probe nuclei [8]. In this work, we have, for the first time, investigated the HFs for 111Cd probe atoms in two FeRh samples of different composition by perturbed γ-γ angular correlation (PAC) spectroscopy in the range from 40 K to a temperature above the TC. The alloy Fe0.48Rh0.52 (A1 sample) is AF at low temperatures. At the temperature Tt = 345 K the first order phase transition is observed, and this compound becomes F at the temperatures lower than TC = 685 K. The alloy Fe0.52Rh0.48 (A2 sample) is only ferromagnetic below TC = 800 K. It was established that in both alloys 111Cd probes substitute only Fe ions. The HFs values extrapolated to 0 K were found to be B1(0) =8.70(5) T and B2(0) =5.53(5) T for AF and F ordering of A1 and A2 samples, respectively. The HF in the AF state is almost 60% higher than the HF in the F alloy. The dependences B1 (T) and B2 (T) show anomalous behavior. At Tt = 345 K, phase transition AF-F is accompanied by a sharp decrease in the HF at 111Cd probe nuclei. Earlier, an increase of the corresponding HFs was observed for 57Fe atoms and 119Sn impurity atoms in the region of AF-F transition by MS in [6] and [8]. Analysis of B1(T) and B2(T) has allowed to obtain the temperature dependences of the competing contributions BFe (T) and BRh (T) to the HFs on 111Cd probe nuclei in FeRh alloys.

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2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.