Materials physics and mechanics

RAR RUS 1-4 University of South Florida Hariharan

USA

Mapping of Switching and Anisotropy Fields in Magnetic Nanoparticles Magnetic nanostructures hold tremendous potential as basic building blocks in spinelectronic devices and high-density data storage. Precise mapping of fundamental parameters like the anisotropy and switching fields over a wide range in temperature and magnetic fields, is essential to understand the influence of the relaxation, interactions and other phenomena that govern the dynamic magnetic properties in these systems. Dynamic radio-frequency transverse susceptibility (χT) experiments provide a very sensitive and unique way to probe these features. We present and discuss the field-dependent transverse susceptibility in two nanoparticle systems: (i) polymer-coated Fe particles and (ii) γ-Fe2 O3 particles synthesized by micelle method. Systematic χT scans at different fixed temperatures reveal variation of the switching and anisotropy fields. Our experiments provide a unique and powerful way to precisely probe the dynamic magnetization in the presence of thermal relaxation and interactions. Magnetic Nanoparticles Switching Anisotropy Fields https://mpm.spbstu.ru/article/2001.5.1/ MPM_4_1_P01.pdf

RAR RUS 5-7 Clarkson University Mozyrsky

NY, USA

Clarkson University Privman

NY, USA

Quantum Computing in Semiconductor Structures with 0.1 µm Separation of Nuclear-spin Qubits Nuclear-spin qubit interactions in a heterostructure can be mediated via the bound outer electrons of impurity atoms whose nuclear spins 1/2 are the qubits. These outer electrons, in turn, interact via the two-dimensional electron gas in the quantum Hall effect regime. We devised a quantum computing scheme, based on this mechanism, with qubit separation of order 0.1 µm, attainable with the present-day semiconductor device technologies, and retaining all the gate-control and measurement aspects of earlier nuclear-spin quantum computing proposals. Semiconductors Structures Quantum Computing https://mpm.spbstu.ru/article/2001.5.2/ MPM_4_1_P02.pdf

RAR RUS 8-12 Sony Corporation Frontier Science Laboratories Ramm

Yokohama, Japan

Sony Corporation Frontier Science Laboratories Ata

Yokohama, Japan

Bundesanstalt für Materialforschung und –prüfung Gross

Berlin, Germany

Bundesanstalt für Materialforschung und –prüfung Unger

Berlin, Germany

Plasma-polymerized C60 Films We studied the polymerization of C60 under different Ar plasma conditions. Films were either deposited in the pressure range between 1.3 and 40 Pa applying input power of 50 W or evaporated C60 films were exposed to Ar plasma of 30 and 50 W. The films were investigated by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and carbon K near-edge X-rayabsorption fine structure spectroscopy (NEXAFS). The films were non-uniform and consisted of unpolymerized C60, dimers, linear chains and polymeric planes. In comparison with evaporated C60 the XPS C 1s peak is broader and asymmetric for the C60 polymer and its shake-up satellites diminished. Furthermore, the features of the valence band as well as the features of the π* antibonding orbitals of the C60 polymer are broader and reduced in intensity. Fullerene C60 Films https://mpm.spbstu.ru/article/2001.5.3/ MPM_4_1_P03.pdf

RAR RUS 13-16 Indian Institute of Technology-Bombay Dapurkar

Mumbai, India

Indian Institute of Technology-Bombay Selvam

Mumbai, India

Encapsulation of Fe2O3 Nanoparticles in Periodic Mesoporous Materials The preparation of iron oxide nanoparticles in the mesopore of silicate MCM-41 and MCM-48 materials is demonstrated. The encapsulation of iron oxy-hydroxides was carried out at room temperature by incipient wetness method and the corresponding oxides were obtained by calcination. This process not only resulted in entrapment of iron oxy-hydroxides / oxides in the mesopores but also led to isomorphous substitution of trivalent iron in the silicate framework. The encapsulated nanoparticles exhibit superparamagnetism while the substituted iron shows paramagnetic behavior. The above is ascertained by using various techniques viz., X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible (DRUV-VIS), electron paramagnetic resonance (EPR), Mössbauer, and magnetic susceptibility measurements. Fe2O3 Nanoparticles Mesoporous Materials https://mpm.spbstu.ru/article/2001.5.4/ MPM_4_1_P04.pdf

RAR RUS 17-21 National University of Singapore Sun

Singapore

National University of Singapore Shen

Singapore

A Practical Nanoscopic Raman Imaging Technique Realized by Near-field Enhancement Near-field scanning optical microscope (NSOM) has the potential to become a very important tool for material characterization due to its ability to investigate the structure and microenvironment of materials in nano-scale by performing spectroscopy as well as topographic mapping. However, near-field Raman results have been rarely reported although Raman spectra are unique in chemical and structural identification. This is due to the fact that Raman signal is intrinsically weak (less than 1 in 107 photons) and the laser power emerging from tip is extremely low (typically 100 nW) because of the low optical throughput of metal coated fiber tips. The long integration time (typically 10 minutes per spectrum) required for collecting good quality Raman spectra makes it impractical to construct a Raman image through this conventional method. In this paper, we report an integration of NSOM and Raman spectrometer using an apertureless configuration, in which the laser is focused onto the sample through a microscope objective and Raman signal is collected by the same objective. This is similar to the conventional microRaman except that a metal tip is brought into the laser spot on sample surface to enhance the Raman signal through surface enhanced Raman scattering (SERS). Raman enhancement of 104 times has been achieved and Raman mapping on real silicon devices has been realized with 1 second exposure time. Furthermore, the reflection scattering geometry employed in our experiments allows the study of any sample without specific sample preparation, unlike the conventional SERS which needs coating samples with metal or growing sample on metal surface. Near-field Enhancement Near-field scanning optical microscope NSOM Surface enhanced Raman scattering SERS https://mpm.spbstu.ru/article/2001.5.5/ MPM_4_1_P05.pdf

RAR RUS 22-24 National University of Singapore Wang

Singapore

National University of Singapore Kuok

Singapore

National University of Singapore Ng

Singapore

National University of Singapore Fan

Singapore

Institute for Microstructural Sciences, National Research Council Lockwood

Ottawa, Canada

Max Planck Institute of Microstructure Physics Nielsch

Halle, Germany

Max Planck Institute of Microstructure Physics Wehrspohn

Halle, Germany

Magnetic and Acoustic Excieations in Confined Nickel Nanowires The magnetic and vibrational excitations of periodic arrays of Ni nanowires, in 1µmthick Al2 O3 membranes on Al substrates, have been investigated by Brillouin scattering. Ni nanowires of 30 and 40 nm diameter and periodicity of 100 nm have been studied in a transverse magnetic field from 0-0.4 T. The p-s polarized spectra feature three peaks, with Brillouin frequencies below 20 GHz, and whose intensities are strongly dependent on the applied magnetic field and whose Stokes/anti-Stokes intensity ratios are unequal. These results indicate that the three peaks are magnetic in origin. A surface acoustic wave on the Ni-filled Al2 O3 structures is also observed in p-p polarized spectra, with a phase velocity of about 3400 m/s for the 30nm-diameter nanowire sample. Al2O3 Membranes Brillouin scattering https://mpm.spbstu.ru/article/2001.5.6/ MPM_4_1_P06.pdf

RAR RUS 25-28 Pohang University of Science and Technology Kim

Pohang, Korea

Institute of Physics, Academia Sinica Hwu Y.K.

Taiwan

Equipe Structure et Comportement Thermomécanique des Matériaux Ruterana

France

Pohang University of Science and Technology Je

Pohang, Korea

Nanostructure of Metal/Semiconductor System by Synchrotron X-ray Scattering We investigated the nano-structural evolution of metal contacts to GaN during annealing and the correlations between nano-structures and electrical properties for two typical ohmic contacts; Pd as a non-alloyed contact and Ni/Au as an alloyed one. Pd was completely transformed to two kinds of epitaxial Pd gallides, Ga2 Pd5 and Ga5 Pd, at 700 ºC. In the alloyed Ni/Au contact, the reaction chemistry was rather complicated. Ni4 N formation was found in N2 annealed sample at 500 ºC of which reaction kinetics was greatly affected by the catalytic effect of Au. The hightemperature compounds were correlated with the rapid degradation of electrical properties during annealing. Meanwhile, the thermal stability of Ni/Au contact greatly improved by suppressing the activated Ni reactivity, which was able to be obtained by forming preferential Ni-O bonding through annealing in air. Nanostructure Metal/Semiconductor Synchrotron X-ray Scattering https://mpm.spbstu.ru/article/2001.5.7/ MPM_4_1_P07.pdf

RAR RUS 29-33 University of Science and Technology of China Li

China

University of Science and Technology of China Zeng

China

University of Science and Technology of China Wang

China

University of Science and Technology of China Wang

China

University of Science and Technology of China Hou

China

Characterization and Manipulation of Nanostructures by a Scanning Tunneling Microscope The recent rapid advances in nanotechnology are due in large part to our newly acquired tools in measuring and manipulating nanostructures, even individual atoms or molecules. As a class of useful tools, scanning probe microscopy, especially scanning tunneling microscopy, provides us the special method to describe the locally physical and chemical properties of nanostructures, and even help us to manipulate nanostructures for constructing new nano-scale apparatus. Here we report our studies on fullerene molecules and quantum dots by using a ultra-high vacuum low-temperature scanning tunneling microscope with emphases on the following aspects: identifying orientational configurations of individual fullerene molecules on different material surface; novel topological order in 2-D C60 domains; single molecule manipulation and negative differential resistance molecular device involving two C60 molecules; size-dependent single electron tunneling effects in 2-D Au clusters; tunable single electron tunneling behavior of ligand-stablized 3-D gold particles; and electrochemical capacitance of a width-variable nano-junction. Nanostructures Scanning Tunneling Microscope https://mpm.spbstu.ru/article/2001.5.8/ MPM_4_1_P08.pdf

RAR RUS 29-33 National Institute for Materials Science Xiong

Tsukuba, Japan

Monash University Finlayson

Clayton, Victoria, Australia

Monash University Muddle

Clayton, Victoria, Australia

The Effect of Boron Content on the Crystallization Behaviour and Microstructure for Nanocrystalline Fe93-xZr7Bx Alloys The crystallization behaviour of amorphous Fe93-xZr7 Bx (x = 3, 6, 12 at.%) alloys and the microstructures of the primary crystallization products have been studied using a combination of differential scanning calorimetry, differential thermal analysis, x-ray diffraction and transmission electron microscopy. For x = 3 and 6 at.% the sole product of primary crystallization is the bcc α-Fe phase. The average grain size of the crystalline phase was 14 nm for the Fe90Zr7 B3 alloy heated to 875K at 20 K/min and 12 nm for the Fe87Zr7 B6 alloy heated to 893K at 20 K/min. However, when x = 12, primary crystallization results in a metastable phase with the cubic “Fe12Si2 ZrB” structure and the α-Fe phase. The average grain size of this metastable phase was 35 nm for the alloy heated to 883K at 20 K/min. Transformation of this metastable phase to predominantly bcc α-Fe can be induced by isothermal heat treatment at sufficiently high temperatures. FeZrB Nanocrystalline Alloys,Crystallization Behaviour Microstructure https://mpm.spbstu.ru/article/2001.5.9/ MPM_4_1_P09.pdf

RAR RUS 39-41 University of Hyderabad Kumar

Hyderabad, India

University of Hyderabad Ray

Hyderabad, India

University of Hyderabad Sunandana

Hyderabad, India

Sb-assisted AgI Nanoparticle Growth in Thin Films The growth of AgI nanoparticles by iodization of Ag1-xSbx thin films under ambient conditions has been investigated. Mechanically well ground mixtures of Ag and Sb were thermally evaporated onto microscopic glass slides. They were subsequently iodized at ambient temperature in the dark and characterized by XRD, SEM and optical measurements. Preliminary results infer that the addition of Sb favors the island growth of AgI, but greatly retards the rate of AgI particle growth, resulting in nanometric sized AgI particles. 5% Sb doped Ag films with optimal thickness (~ 200 Å) are found to be ideal for the formation and long term stabilization of γ-AgI thin films. Sb also plays a crucial role in controlling the exciton formation process. AgI Nanoparticle Thin Films https://mpm.spbstu.ru/article/2001.5.10/ MPM_4_1_P10.pdf

RAR RUS 42-45 National University of Singapore Ho

Singapore

National University of Singapore Choi

Singapore

The Singapore-MIT Alliance Heng

Singapore

National University of Singapore Ng

Singapore

Effect of Laser on Formation of Ge Nanocrystal Embedded in SiO2 We investigate the possibility of using laser for the synthesis of Ge nanocystals in the co-sputtered Ge + SiO2 samples. The laser annealed samples, that were sputtered with ≥ 4 cm2 of Ge attached to the target, exhibited a Raman peak at ~ 290 cm-1. The peak sharpened as the laser beam exposure time increased. However, the peak position was significantly lower than the position of bulk Ge (300 cm-1) peak. It is possible that a structural change in the Ge nanocrystals or stress in the films has caused the peak position to be lower than the bulk Ge value. The photoluminescence (PL) intensity of the laser annealed samples was also considerably weaker as compared to samples that were synthesized by rapid thermal annealing. Ge Nanocrystal Laser on Formation https://mpm.spbstu.ru/article/2001.5.11/ MPM_4_1_P11.pdf

RAR RUS 46-50 National University of Singapore Choi

Singapore

National University of Singapore Ho

Singapore

National University of Singapore Ng

Singapore

Effect of Size of Ge Nanocrystals Embedded in SiO2 on Raman Spectra In this paper, we investigate the effect of Ge nanocrystal size on the Raman results. The Ge nanocrystal size distributions of samples rapid thermally annealed at 800 and 1000 °C for 300 s were obtained from the TEM pictures. We constructed the theoretical Raman spectrum based on the phonon confinement model taking into account of the size distribution of the nanocrystals. By taking into account of the Ge nanocrystal size distribution, we found a good fit between the experimental and theoretical Raman results at the lower wavenumber portion from the Raman peak for samples annealed at 800 and 1000 °C. Our model, however, is not able to account for the portion in the Raman spectra above the Raman peak. We suggest that stress in the annealed films maybe responsible for this discrepancy. Ge Nanocrystals Raman Spectra https://mpm.spbstu.ru/article/2001.5.12/ MPM_4_1_P12.pdf

RAR RUS 51-55 Institute of High Performance Computing Lu

Singapore

Institute of High Performance Computing Shen

Singapore

Institute of Materials Research & Engineering O’Shea

Singapore

Institute of High Performance Computing Lee

Singapore

Institute of High Performance Computing Ng

Singapore

Analysis of Surface Effects on Mechanical Properties of Microcantilevers In this paper, some problems concerning surface effects of microcantilever-based sensors are discussed. The problems include the influence on surface Q changes due to the variation of position and length of a coated film, and frequency changes induced by tensile or compressive surface stresses. Some useful results are obtained based on theoretical analysis, which are of interest in the design and fabrication of microcantilever based sensors. Microcantilevers Mechanical Properties Surface Effects https://mpm.spbstu.ru/article/2001.5.13/ MPM_4_1_P13.pdf

RAR RUS 56-61 National University of Singapore Yin

Singapore

National University of Singapore Chan

Singapore

National University of Singapore Chow G.M.

Singapore

Nanostructured Iron-Nickel Thin Films Synthesized by Electroless Polyol Deposition Fex Ni100-x thin films were deposited on conductive (Cu) and non-conductive (Pd activated glass) substrate using an electroless, polyol method. The stoichiometry of film composition, as compared to the precursor concentration, strongly depended on the substrate position. When the substrate was immersed in the refluxing solution, Fe-deficient films were deposited. However Fe-rich films were synthesized when the substrates were suspended in the vapor phase above the solution. When the substrate was repeatedly suspended above the solution for a short time after each long immersion in solution (this process was denoted as quenching), the films developed an intermediate range of Fe concentration. The surface microstructure, long range and short range orders of these films revealed that the films were oxidized, and the extent of oxidation depended both on the type of substrate and substrate position. Iron-Nickel films Nanostructured Films Electroless Polyol Deposition https://mpm.spbstu.ru/article/2001.5.14/ MPM_4_1_P14.pdf

RAR RUS 62-66 National Tsing Hua University Chen

Taiwan

National Tsing Hua University Chiu

Taiwan

National Tsing Hua University Perng

Taiwan

On the Photoluminescence of Si Nanoparticles Silicon nanoparticles with diameters ranging from 3 to 50 nm were prepared by thermal evaporation. The nanoparticles showed visible light emissions from 5000 Å to 9000 Å, with peak intensity at 8000-8200 Å, when excited with a He-Cd laser. The intensity increased with decreasing particle size. Based on the photoluminescence (PL) characteristics, it is suggested that the PL for particles larger than 9 nm is surface state-induced, while the PL for those smaller than 9 nm is ascribed to quantum confinement effects. Silicon Si Nanoparticles Photoluminescence https://mpm.spbstu.ru/article/2001.5.15/ MPM_4_1_P15.pdf

RAR RUS 67-70 Waseda University Yamada

Tokyo, Japan

Waseda University Takano

Tokyo, Japan

Waseda University Yamada

Tokyo, Japan

Waseda University Yoshitomi

Tokyo, Japan

Waseda University Inoue

Tokyo, Japan

Waseda University Osaka

Tokyo, Japan

Applicability of Alkyl Monolayers on Si(111) Towards Practical Nano-scale Fabrication A novel process of electron-beam nanometer-scale fabrication on Si(111) wafer surfaces has been proposed on the basis of application of alkyl monolayers as the patterning media. The alkyl (Cn H2n+1-) monolayers prepared with the Grignard reagents were subjected to electronbeam patterning with ambient O2 and deposition of metals onto the formed patterns by immersion into aqueous solutions containing metal ions. The tolerance of alkyl-covered Si(111) surface towards aqueous solutions has been demonstrated. The alkyl monolayer survived in Cu deposition solution containing HF, even while a visible amount of Cu deposit was built up. Alkyl Monolayers Silicon Nano-scale Fabrication https://mpm.spbstu.ru/article/2001.5.16/ MPM_4_1_P16.pdf