“Interface controlled electronic variations in correlated heterostructures”. Gehrke K, Moshnyaga V, Samwer K, Lebedev OI, Verbeeck J, Kirilenko D, Van Tendeloo G, Physical review : B : condensed matter and materials physics 82, 113101 (2010). http://doi.org/10.1103/PhysRevB.82.113101
Abstract: An interface modification of (LaCa)MnO3-BaTiO3 superlattices was found to massively influence magnetic and magnetotransport properties. Moreover it determines the crystal structure of the manganite layers, changing it from orthorhombic (Pnma) for the conventional superlattice (cSL), to rhombohedral (R3̅ c) for the modified one (mSL). While the cSL shows extremely nonlinear ac transport, the mSL is an electrically homogeneous material. The observations go beyond an oversimplified picture of dead interface layers and evidence the importance of electronic correlations at perovskite interfaces.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 9
DOI: 10.1103/PhysRevB.82.113101
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“Interfacial spin glass state and exchange bias in manganite bilayers with competing magnetic orders”. Ding JF, Lebedev OI, Turner S, Tian YF, Hu WJ, Seo JW, Panagopoulos C, Prellier W, Van Tendeloo G, Wu T, Physical review : B : condensed matter and materials physics 87, 054428 (2013). http://doi.org/10.1103/PhysRevB.87.054428
Abstract: The magnetic properties of manganite bilayers composed of G-type antiferromagnetic (AFM) SrMnO3 and double-exchange ferromagnetic (FM) La0.7Sr0.3MnO3 are studied. A spin-glass state is observed as a result of competing magnetic orders and spin frustration at the La0.7Sr0.3MnO3/SrMnO3 interface. The dependence of the irreversible temperature on the cooling magnetic field follows the Almeida-Thouless line. Although an ideal G-type AFM SrMnO3 is featured with a compensated spin configuration, the bilayers exhibit exchange bias below the spin glass freezing temperature, which is much lower than the Néel temperature of SMO, indicating that the exchange bias is strongly correlated with the spin glass state. The results indicate that the spin frustration that originates from the competition between the AFM super-exchange and the FM double-exchange interactions can induce a strong magnetic anisotropy at the La0.7Sr0.3MnO3/SrMnO3 interface.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 98
DOI: 10.1103/PhysRevB.87.054428
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“Metal to insulator transition in the n-type hollandite vanadate Pb1.6V8O16”. Maignan A, Lebedev OI, Van Tendeloo G, Martin C, Hebert S, Physical review : B : condensed matter and materials physics 82, 035122 (2010). http://doi.org/10.1103/PhysRevB.82.035122
Abstract: The transport and magnetic measurements of polycrystalline Pb1.6V8O16 hollandite reveal a concomitant metal to insulator and antiferromagnetic transition at TMI≈140 K. A clear localization is found below TMI, evidenced by a rapid increase in the absolute value of the negative Seebeck coefficient. The structural study by x-ray and transmission electron microscopy confirms the hollandite structure and shows that no structural transition occurs at TMI, ruling out a possible charge orbital ordering. The negative Seebeck coefficient observed from 50 K up to 900 K, with values reaching S=−38 μV K−1 at 900 K, is explained by the electron doping of ∼1.4e− in the V empty t2g orbitals responsible for the bad metal resistivity (ρ900 K∼2 mΩ cm). As this S value is close to that obtained by considering only the spin and orbital degeneracies, it is expected that |S| for such vanadates will not be sensitive at high temperature to the t2g band filling
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 10
DOI: 10.1103/PhysRevB.82.035122
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“Phase transition and magnetic anisotropy of (La,Sr)MnO3 thin films”. Wang Z-H, Kronmüller H, Lebedev OI, Gross GM, Razavi FS, Habermeier HU, Shen BG, Physical review : B : condensed matter and materials physics 65, 054411 (2002). http://doi.org/10.1103/PhysRevB.65.054411
Abstract: The magnetic proper-ties and their correlation with the microstructure and electrical transport are investigated in La0.88Sr0.1MnO3 films grown on (100)SrTiO3 Single crystal substrates with thickness ranging from 100 to 2500 Angstrom. The ultrathin film (t = 100 Angstrom) has a single ferromagnetic transition (FMT) at T-c of 250 K, whereas the thicker films exhibit two FMTs, with the main one at a lowered T-c of 200 K while the minor one around 300 K. Furthermore, a thickness dependent magnetic anisotropy has been found, strongly indicating the existence of strain effect, which is also revealed by the transmission electron microscopy study. The suppressed Jahn-Teller distortion (JTD) by the epitaxial strain, and the recovered JTD due to the strain relexation are suggested to explain the metallic behavior in thin films and the insulating behavior in the thick film (t = 2500 Angstrom), repectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 23
DOI: 10.1103/PhysRevB.65.054411
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“Proximity induced metal-insulator transition in YBa2Cu3O7/La2/3Ca1/3MnO3 superlattices”. Holden T, Habermeier H-U, Cristiani G, Golnik A, Boris A, Pimenov A, Humlicek J, Lebedev OI, Van Tendeloo G, Keimer B, Bernhard C, Physical review : B : condensed matter and materials physics 69, 064505 (2004). http://doi.org/10.1103/PhysRevB.69.064505
Abstract: The far-infrared dielectric response of superlattices (SL) composed of superconducting YBa2Cu3O7 (YBCO) and ferromagnetic La0.67Ca0.33MnO3 (LCMO) has been investigated by ellipsometry. A drastic decrease of the free-carrier response is observed which involves an unusually large length scale of d(crit)approximate to20 nm in YBCO and d(crit)approximate to10 nm in LCMO. A corresponding suppression of metallicity is not observed in SL's where LCMO is replaced by the paramagnetic metal LaNiO3. Our data suggest that either a long-range charge transfer from the YBCO to the LCMO layers or alternatively a strong coupling of the charge carriers to the different and competitive kind of magnetic correlations in the LCMO and YBCO layers is at the heart of the observed metal-insulator transition. The low free-carrier response observed in the far-infrared dielectric response of the magnetic superconductor RuSr2GdCu2O8 is possibly related to this effect.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 101
DOI: 10.1103/PhysRevB.69.064505
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“Structural and magnetic properties of the colossal magnetoresistance perovskite La0.85Ca0.15MnO3”. Lobanov MV, Balagurov AM, Pomjakushin VJ, Fischer P, Gutmann M, Abakumov AM, D'yachenko OG, Antipov EV, Lebedev OI, Van Tendeloo G, Physical review : B : condensed matter and materials physics 61, 8941 (2000). http://doi.org/10.1103/PhysRevB.61.8941
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 47
DOI: 10.1103/PhysRevB.61.8941
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“Structural phase transition and spontaneous interface reconstruction in La2/3Ca1/3MnO3/BaTiO3 superlattices”. Turner S, Lebedev OI, Verbeeck J, Gehrke K, Moshnyaga V, Van Tendeloo G, Physical review : B : condensed matter and materials physics 87, 035418 (2013). http://doi.org/10.1103/PhysRevB.87.035418
Abstract: (La2/3Ca1/3MnO3)n/(BaTiO3)m (LCMOn/BTOm) superlattices on MgO and SrTiO3 substrates with different layer thicknesses (n = 10, 38, 40 and m = 5, 18, 20) have been grown by metal organic aerosol deposition (MAD) and have been fully characterized down to the atomic scale to study the interface characteristics. Scanning transmission electron microscopy combined with spatially resolved electron energy-loss spectroscopy provides clear evidence for the existence of atomically sharp interfaces in MAD grown films, which exhibit epitaxial growth conditions, a uniform normal strain, and a fully oxidized state. Below a critical layer thickness the LCMO structure is found to change from the bulk Pnma symmetry to a pseudocubic R3̅ c symmetry. An atomically flat interface reconstruction consisting of a single Ca-rich atomic layer is observed on the compressively strained BTO on LCMO interface, which is thought to partially neutralize the total charge from the alternating polar atomic layers in LCMO as well as relieving strain at the interface. No interface reconstruction is observed at the tensile strained LCMO on BTO interface.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 12
DOI: 10.1103/PhysRevB.87.035418
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“Structural phase transitions and stress accommodation in (La0.67Ca0.33MnO3)1.x:(MgO)x composite films”. Lebedev OI, Verbeeck J, Van Tendeloo G, Shapoval O, Belenchuk A, Moshnyaga V, Damaschke B, Samwer K, Physical review : B : condensed matter and materials physics 66, 104421 (2002). http://doi.org/10.1103/PhysRevB.66.104421
Abstract: Composite (La0.67Ca0.33MnO3)(1-x):(MgO)(x) films were prepared by metalorganic aerosol deposition on a (100)MgO substrate for different concentrations of the (MgO) phase (0less than or equal toxless than or equal to0.8). At xapproximate to0.3 a percolation threshold in conductivity is reached, at which an infinite insulating MgO cluster forms around the La0.67Ca0.33MnO3 grains. This yields a drastic increase of the electrical resistance for films with x>0.3. The film structure is characterized by x-ray diffraction and transmission electron microscopy. The local structure of the La0.67Ca0.33MnO3 within the film depends on the MgO concentration which grows epitaxially along the domain boundaries. A different structural phase transition from the orthorhombic Pnma structure to an unusual rhombohedral R (3) over barc structure at the percolation threshold xapproximate to0.3 is found for La0.67Ca0.33MnO3. A three-dimensional stress accommodation in thick films through a phase transition is suggested.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 48
DOI: 10.1103/PhysRevB.66.104421
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“Structure and microstructure of La1-xCaxMnO3- thin films prepared by pulsed layer deposition”. Lebedev OI, Van Tendeloo G, Amelinckx S, Leibold B, Habermeier H-U, Physical review : B : condensed matter and materials physics 58, 8065 (1998). http://doi.org/10.1103/PhysRevB.58.8065
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 131
DOI: 10.1103/PhysRevB.58.8065
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“Structure-properties relationship in ferromagnetic superconducting RuSr2GdCu2O8”. Lebedev OI, Van Tendeloo G, Cristiani G, Habermeier H-U, Matveev AT, Physical review : B : condensed matter and materials physics 71, 134523 (2005). http://doi.org/10.1103/PhysRevB.71.134523
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 16
DOI: 10.1103/PhysRevB.71.134523
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“Superconductivity and microstructure of YSr2Cu3O6.875”. Lebedev OI, Van Tendeloo G, Licci F, Gilioli E, Gauzzi A, Prodi A, Marezio M, Physical review : B : condensed matter and materials physics 66, 132510 (2002). http://doi.org/10.1103/PhysRevB.66.132510
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 9
DOI: 10.1103/PhysRevB.66.132510
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“SrTiO3(100)/(LaMnO3)m(SrMnO3)n layered heterostructures: a combined EELS and TEM study”. Verbeeck J, Lebedev OI, Van Tendeloo G, Mercey B, Physical review : B : condensed matter and materials physics 66, 184426 (2002). http://doi.org/10.1103/PhysRevB.66.184426
Abstract: Epitaxially grown heterostructures consisting of alternating layers of LaMnO(3) (LMO, 9 or 15 unit cells) and SrMnO(3) (SMO, 4 or 6 unit cells) on a SrTiO(3)(100) (STO(100)) substrate have been studied by a combination of high resolution transmission electron microscopy (HRTEM), electron diffraction, quantitative electron energy loss spectroscopy (EELS) with model fitting, energy filtered TEM (EFTEM) and imaging spectroscopy on an atomic scale. The combination of these techniques is necessary for the structural, chemical, and electronic characterization of these heterostructures. A model is proposed containing chemically and structurally sharp interfaces. The SrMnO(3) layers are stabilized in a Pm3m structure between two LMO layers. Tensile stress causes oxygen deficiency in the SMO layers increasing the number of 3d electrons on the Mn sites to resemble the Mn(3+) sites in LMO. The energy loss near edge structure (ELNES) of O and Mn is compared for both LMO and SMO layers and shows that the Mn-O bonds have a partially covalent character. The absence of a strong valency effect in the Mn ELNES is due to the oxygen vacancies in SMO.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 32
DOI: 10.1103/PhysRevB.66.184426
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“Immersion calorimetry as a tool to evaluate the catalytic performance of titanosilicate materials in the epoxidation of cyclohexene”. Vernimmen J, Guidotti M, Silvestre-Albero J, Jardim EO, Mertens M, Lebedev OI, Van Tendeloo G, Psaro R, Rodríguez-Reinoso F, Meynen V, Cool P, Langmuir: the ACS journal of surfaces and colloids 27, 3618 (2011). http://doi.org/10.1021/la104808v
Abstract: Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts. Moreover, for the first time, immersion calorimetry with the same substrate molecule as in the catalytic test reaction is applied as an extra means to interpret the catalytic results. A good correlation between catalytic performance and immersion calorimetry results is found. This work points out that the combination of catalytic testing and immersion calorimetry can lead to important insights into the influence of the materials structural characteristics on catalysis. Moreover, the potential of using immersion calorimetry as a screening tool for catalysts in epoxidation reactions is shown.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.833
Times cited: 19
DOI: 10.1021/la104808v
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“Tailored vapor-phase growth of CuxO-TiO2(x=1,2) nanomaterials decorated with Au particles”. Barreca D, Carraro G, Gasparotto A, Maccato C, Lebedev OI, Parfenova A, Turner S, Tondello E, Van Tendeloo G, Langmuir: the ACS journal of surfaces and colloids 27, 6409 (2011). http://doi.org/10.1021/la200698t
Abstract: We report on the fabrication of CuxOTiO2 (x = 1, 2) nanomaterials by an unprecedented vapor-phase approach. The adopted strategy involves the growth of porous CuxO matrices by means of chemical vapor deposition (CVD), followed by the controlled dispersion of TiO2 nanoparticles. The syntheses are performed on Si(100) substrates at temperatures of 400550 °C under wet oxygen atmospheres, adopting Cu(hfa)2·TMEDA (hfa =1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N′,N′-tetramethylethylenediamine) and Ti(O-iPr)2(dpm)2 (O-iPr = isopropoxy; dpm = 2,2,6,6-tetramethyl-3,5-heptanedionate) as copper and titanium precursors, respectively. Subsequently, finely dispersed gold nanoparticles are introduced in the as-prepared systems via radio frequency (RF)-sputtering under mild conditions. The synthesis process results in the formation of systems with chemical composition and nano-organization strongly dependent on the nature of the initial CuxO matrix and on the deposited TiO2 amount. The decoration with low-size gold clusters paves the way to the engineering of hierarchically organized nanomaterials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.833
Times cited: 36
DOI: 10.1021/la200698t
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“Deposition of vanadium silicalite-1 nanoparticles on SBA-15 materials: structural and transport characteristics of SBA-VS-15”. Meynen V, Cool P, Vansant EF, Kortunov P, Grinberg F, Kärger J, Mertens M, Lebedev OI, Van Tendeloo G, Microporous and mesoporous materials 99, 14 (2007). http://doi.org/10.1016/j.micromeso.2006.08.029
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.615
Times cited: 23
DOI: 10.1016/j.micromeso.2006.08.029
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“Formation of a combined micro- and mesoporous material using zeolite Beta nanoparticles”. van Oers CJ, Stevens WJJ, Bruijn E, Mertens M, Lebedev OI, Van Tendeloo G, Meynen V, Cool P, Microporous and mesoporous materials: zeolites, clays, carbons and related materials 120, 29 (2009). http://doi.org/10.1016/j.micromeso.2008.08.056
Abstract: Composite micro- and mesoporous materials are synthesized using zeolite Beta nanoparticles without the need for a structure directing agent to form the mesopores. This leads to important ecological and economical advantages. The influence of the way of cooling the aged nanoparticles solution on the formation of the composite materials has been studied. The materials have been characterized towards porosity by N2-sorption, towards zeolitic properties by TGA, DRIFT, XRD and TEM, towards aluminium content by EPMA. All prepared structures possess zeolitic properties. However, the method of cooling down of the aged seeds leads to differences in the porosity and intensity of the zeolitic characteristics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.615
Times cited: 42
DOI: 10.1016/j.micromeso.2008.08.056
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“The merging of silica-surfactant microspheres under hydrothermal conditions”. Liu S, Lebedev OI, Mertens M, Meynen V, Cool P, Van Tendeloo G, Vansant EF, Microporous and mesoporous materials: zeolites, clays, carbons and related materials 116, 141 (2008). http://doi.org/10.1016/j.micromeso.2008.03.034
Abstract: Post-synthesis hydrothermal treatments have been used to improve the quality of MCM-41 materials. In our latest work, merging of surfactant-containing silica microspheres during the hydrothermal treatments was observed. Mechanistic insights and the different stages that are involved in the merging process can be summarized as follows. First, the surfaces of the starting microspheres open up due to the dissolution of silica. Then the dissolved silica species provide mass source for the formation of particle necks connecting two neighboring microspheres. Gradually, surfaces of the starting microspheres are flattened to meet the needs of further growth of the necks. Finally, some chain-like highly-ordered mesoporous structures up to several micrometers are formed. The observed merging of the surfactant-containing microspheres is a re-assembling process, which is under the control of electrostatic force between the dissolved silica species and the surfactant cations. The occluded surfactant cations in the precursor spheres play important roles in the merging process.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.615
Times cited: 5
DOI: 10.1016/j.micromeso.2008.03.034
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“Mesoporous material formed by acidic hydrothermal assembly of silicalite-1 precursor nanoparticles in the absence of meso-templates”. Stevens WJJ, Meynen V, Bruijn E, Lebedev OI, Van Tendeloo G, Cool P, Vansant EF, Microporous and mesoporous materials: zeolites, clays, carbons and related materials 110, 77 (2008). http://doi.org/10.1016/j.micromeso.2007.09.007
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.615
Times cited: 21
DOI: 10.1016/j.micromeso.2007.09.007
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“Synthesis and characterization of the new cyclosilicate hydrate (hexamethyleneimine)4.[Si8O16(OH)4].12H2O”. Verlooy PLH, Robeyns K, van Meervelt L, Lebedev OI, Van Tendeloo G, Martens JA, Kirschhock CEA, Microporous and mesoporous materials: zeolites, clays, carbons and related materials 130, 14 (2010). http://doi.org/10.1016/j.micromeso.2009.10.006
Abstract: A new cyclosilicate hydrate with composition (C6H14N)4·[Si8O16(OH)4]·12H2O was crystallized and the structure determined by single-crystal X-ray diffraction. The structure, described by the tetragonal space group I41/a, with unit cell dimensions of a = 39.2150(2) Å and c = 14.1553(2) Å, contains columns of hydrogen-bonded cubic octamer silicate anions. The space between silicate columns holds hydrogen-bonded water and protonated hexamethyleneimine molecules compensating the negative charge of the silicate. The crystal water can be removed resulting in a rearrangement of the columns into orthorhombic symmetry. Removal of the organic moiety causes amorphisation. Flash evacuation results in a new microporous material with pore volumes typical of a zeolite.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.615
Times cited: 5
DOI: 10.1016/j.micromeso.2009.10.006
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“Plasma-assisted synthesis of Ag/ZnO nanocomposites : first example of photo-induced H2 production and sensing”. Simon Q, Barreca D, Bekermann D, Gasparotto A, Maccato C, Comini E, Gombac V, Fornasiero P, Lebedev OI, Turner S, Devi A, Fischer RA, Van Tendeloo G, International journal of hydrogen energy 36, 15527 (2011). http://doi.org/10.1016/j.ijhydene.2011.09.045
Abstract: Ag/ZnO nanocomposites were developed by a plasma-assisted approach. The adopted strategy exploits the advantages of Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) for the growth of columnar ZnO arrays on Si(100) and Al2O3 substrates, in synergy with the infiltration power of the Radio Frequency (RF)-sputtering technique for the subsequent dispersion of different amounts of Ag nanoparticles (NPs). The resulting composites, both as-prepared and after annealing in air, were thoroughly characterized with particular attention on their morphological organization, structure and composition. For the first time, the above systems have been used as catalysts in the production of hydrogen by photo-reforming of alcoholic solutions, yielding a stable H2 evolution even by the sole use of simulated solar radiation. In addition, Ag/ZnO nanocomposites presented an excellent response in the gas-phase detection of H2, opening attractive perspectives for advanced technological applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.582
Times cited: 62
DOI: 10.1016/j.ijhydene.2011.09.045
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“Controlled vapor-phase synthesis of cobalt oxide nanomaterials with tuned composition and spatial organization”. Barreca D, Gasparotto A, Lebedev OI, Maccato C, Pozza A, Tondello E, Turner S, Van Tendeloo G, CrystEngComm 12, 2185 (2010). http://doi.org/10.1039/b926368n
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.474
Times cited: 85
DOI: 10.1039/b926368n
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“Defect controlled room temperature ferromagnetism in Co-doped barium titanate nanocrystals”. Ray S, Kolen'ko YV, Kovnir KA, Lebedev OI, Turner S, Chakraborty T, Erni R, Watanabe T, Van Tendeloo G, Yoshimura M, Itoh M, Nanotechnology 23, 025702 (2012). http://doi.org/10.1088/0957-4484/23/2/025702
Abstract: Defect mediated high temperature ferromagnetism in oxide nanocrystallites is the central feature of this work. Here, we report the development of room temperature ferromagnetism in nanosized Co-doped barium titanate particles with a size of around 14 nm, synthesized by a solvothermal drying method. A combination of x-ray diffraction with state-of-the-art electron microscopy techniques confirms the intrinsic doping of Co into BaTiO3. The development of the room temperature ferromagnetism was tracked down to the different donor defects, namely hydroxyl groups at the oxygen site (\mathrm {OH}\mathrm {(O)}
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 19
DOI: 10.1088/0957-4484/23/2/025702
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“Structural and luminescence investigation on gadolinium gallium garnet nanocrystalline powders prepared by solution combustion synthesis”. Krsmanovic R, Morozov VA, Lebedev OI, Polizzi S, Speghini A, Bettinelli M, Van Tendeloo G, Nanotechnology 18, 325604 (2007). http://doi.org/10.1088/0957-4484/18/32/325604
Abstract: Nanocrystalline powders of undoped and lanthanide (Pr3+, Tm3+)- doped gadolinium gallium garnet, Gd3Ga5O12 (GGG), were prepared by propellant synthesis and studied by x-ray powder diffraction (XRD), electron diffraction (ED), high-resolution electron microscopy (HREM) and luminescence spectroscopy. The x-ray diffraction patterns of the GGG samples were analysed using the Rietveld method. The Rietveld refinement reveals the existence of two garnet-type phases: both are cubic (space group Ia $(3) over bar $d) with a slightly different lattice parameter and probably a slightly different composition. Electron diffraction and electron microscopy measurements confirm the x-ray diffraction results. EDX measurements for lanthanide-doped samples show that stable solid solutions with composition Gd(3-x)Ln(x)Ga(5)O(12), x approximate to 0.3 ( Ln = Pr; Tm) have been obtained. The luminescence properties of the Tm3+ -doped nanocrystalline GGG samples were measured and analysed.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 33
DOI: 10.1088/0957-4484/18/32/325604
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“Structural characterization and luminescence properties of nanostructured lanthanide-doped Sc2O3 prepared by propellant synthesis”. Krsmanovic R, Lebedev OI, Speghini A, Bettinelli M, Polizzi S, Van Tendeloo G, Nanotechnology 17, 2805 (2006). http://doi.org/10.1088/0957-4484/17/11/013
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 22
DOI: 10.1088/0957-4484/17/11/013
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“Structure and defect characterization of multiferroic <tex>ReMnO$3 films and multilayers by TEM”. Jehanathan N, Lebedev O, Gélard I, Dubourdieu C, Van Tendeloo G, Nanotechnology 21, 075705 (2010). http://doi.org/10.1088/0957-4484/21/7/075705
Abstract: Epitaxial rare earth manganite thin films (ReMnO3; Re = Tb, Ho, Er, and Y) and multilayers were grown by liquid injection metal organic chemical vapor deposition (MOCVD) on YSZ(111) and the same systems were grown c-oriented on Pt(111) buffered Si substrates. They have been structurally investigated by electron diffraction (ED) and high resolution transmission electron microscopy (HRTEM). Nanodomains of secondary orientation are observed in the hexagonal YMnO3 films. They are related to a YSZ(111) and Pt(111) misorientation. The epitaxial film thickness has an influence on the defect formation. TbO2 and Er2O3 inclusions are observed in the TbMnO3 and ErMnO3 films respectively. The structure and orientation of these inclusions are correlated to the resembling symmetry and structure of film and substrate. The type of defect formed in the YMnO3/HoMnO3 and YMnO3/ErMnO3 multilayers is also influenced by the type of substrate they are grown on. In our work, atomic growth models for the interface between the film/substrate are proposed and verified by comparison with observed and computer simulated images.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.44
Times cited: 15
DOI: 10.1088/0957-4484/21/7/075705
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“Doping of interfaces in (La0.7Sr0.3MnO3)1-x:(MgO)x composite films”. Köster S, Moshnyaga V, Samwer K, Lebedev OI, Van Tendeloo G, Shapoval O, Belenchuk A, Applied physics letters 81, 1648 (2002). http://doi.org/10.1063/1.1503849
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 35
DOI: 10.1063/1.1503849
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“Electron energy-loss spectroscopy study of a (LaMnO3)8(SrMnO3)4 heterostructure”. Verbeeck J, Lebedev OI, Van Tendeloo G, Silcox J, Mercey B, Hervieu M, Haghiri-Gosnet AM, Applied physics letters 79, 2037 (2001). http://doi.org/10.1063/1.1403316
Abstract: An epitaxially grown heterostructure consisting of alternating layers of LaMnO3 (8 unit cells) and SrMnO3 (4 unit cells) on a SrTiO3 substrate has been studied by a combination of electron energy-loss spectroscopy (EELS) and high-resolution transmission electron microscopy (HRTEM) on an atomic scale. Excitation edges of all elements are captured with subnanometer spatial accuracy, and parametrized to obtain chemical profiles. The fine-edge structure of O K and Mn L-2,L-3 edges are interpreted as signatures of the local electronic structure and show a spatial modulation of the concentration of holes with O 2p character. The chemical concentration is found to be different for the bottom and top interface of a SrMnO3 layer. HRTEM complements the EELS results and confirms the asymmetry of the interfaces. (C) 2001 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 19
DOI: 10.1063/1.1403316
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“Epitaxial strain induced metal insulator transition in La0.9Sr0.1MnO3 and La0.88Sr0.1MnO3 thin films”. Razavi FS, Gross G, Habermeier H-U, Lebedev O, Amelinckx S, Van Tendeloo G, Vigliante A, Applied physics letters 76, 155 (2000). http://doi.org/10.1063/1.125687
Abstract: We are reporting an unexpected metal insulator transition at the ferromagnetic phase-transition temperature for thin films of La0.9Sr0.1MnO3 (< 50 nm), grown on a (100) face of SrTiO3 substrate. For the thicker films (> 50 nm), similar to the single crystal, no such transition is observed below T-C. Additionally, we observe the suppression of the features associated with charge or orbital ordering in intentionally La-deficient thin films of La0.88Sr0.1MnO3 (< 75 nm). In thin films, transmission electron microscopy reveals a compressive strain due to the epitaxial growth, that is, lattice parameters adopt those of the cubic lattice of SrTiO3. As the film thickness increases, coherent microtwinning is observed in the films and the films relax to a orthorhombic structure. (C) 2000 American Institute of Physics. [S0003-6951(00)00402-2].
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 91
DOI: 10.1063/1.125687
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“Ga segregation in DyBa2Cu3O7-\delta/PrBa2Cu3-xGaxO7-\delta/DyBa2Cu3O7-\delta ramp-type Josephson junctions”. Verbist K, Lebedev OI, Van Tendeloo G, Verhoeven MAJ, Rijnders AJHM, Blank DHA, Rogalia H, Applied physics letters 70, 1167 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 8
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“Negative magnetoresistance in a V3+/V4+ mixed valent vanadate”. Maignan A, Lebedev OI, Van Tendeloo G, Martin C, Hébert S, Applied physics letters 96, 232502 (2010). http://doi.org/10.1063/1.3446892
Abstract: The magnetotransport and magnetic properties of the PbV6O11 vanadate, crystallizing in the P63mc space group, reveal the existence of a negative magnetoresistance related to its ferromagnetic state (TC ∼ 90 K). The maximum effect is observed at 20 K reaching −30% in 9 T. The structural study of this ceramic reveals a V/Pb ratio smaller than expected from the formula. This is explained by the presence of numerous stacking faults observed by high resolution transmission electron microscopy. The existence of these planar defects acting as resistive barriers along the c axis could be responsible for tunneling magnetoresistance.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
DOI: 10.1063/1.3446892
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