Publications

Displaying 126 - 150 of 264

Workshop on Measurement Needs for Local-Structure Determination in Inorganic Materials

November 8, 2008

Author(s)

Igor Levin, Terrell A. Vanderah

The functional responses (e.g. dielectric, magnetic, catalytic, etc) of many industrially-relevant materials are controlled by their local structure a term that refers to the atomic arrangements on a scale ranging from atomic (sub-nanometer) to several

Combinatorial Studies of Ba-Y-Cu-O Films for Coated-Conductor Applications

October 23, 2008

Author(s)

Winnie K. Wong-Ng, Makoto Otani, Igor Levin, Peter K. Schenck, Zhi Yang, Guangyao Liu, Lawrence P. Cook, Ron Feenstra, Wei Zheng, Marty Rupich

Phase relationships in bulk and thin film Ba-Y-Cu-O high-Tc superconductor system were determined at processing conditions relevant for industrial production of coated conductors. Our results demonstrated that the absence of BaY2CuO5 (which has a critical

Crystal Structure of the Layered Perovskite-Like Sr n (Nb,Ti) n O 3n+2 Compounds

October 16, 2008

Author(s)

Igor Levin, Leonid A. Bendersky

The effects of combinations of octadedral tilts on the symmetries of layered A nB nX 3n+2 structures were considered. Two complimentary approaches were used to deduce the symmetries of tilted layered structures. The space groups associated with different

Crystal Structure of the Layered Perovskite-Like Sr n (Nb,Ti) n O 3n+2 Compounds. Part II. TEM Study of the Sr n (Nb,Ti) n O 3n+2

October 16, 2008

Author(s)

Igor Levin, Leonid A. Bendersky, Terrell A. Vanderah

Series of Srn(Nb,Ti) nO 3n+2 structures with n=4,4.5,5,6 and 7 were studies by transmission electron microscopy. These structures are composed of inifite two-dimensional slabs of the distorted perovskite structure that are n' (Ti,Nb)O6 octahedra thick and

Fabrication of GaN-Based Nanoscale Device Structures Utilizing Focused Ion Beam Induced Pt Deposition

October 16, 2008

Author(s)

Abhishek Motayed, Albert Davydov, Mark D. Vaudin, Igor Levin, John Melngailis, S N. Mohammad

In this work we have demonstrated nanoscale GaN device structures made from individual GaN nanowires and electrical contacts utilizing Focused Ion Beam (FIB) induced Pt deposition. These GaN nanowires were grown by direct reaction of Ga vapor with NH-

Growth, Crystal Structure, and Properties of Epitaxial BiScO3 Thin Films

August 15, 2008

Author(s)

Igor Levin, Susan Trolier-McKinstry, Michael D. Biegalski, Junling Wang, Alexei A. Belik, E. Takayama-Muromachi

Epitaxial thin films of BiScO3, a compound which is thermodynamically unstable under ambient conditions, were grown on BiFeO3-buffered SrTiO3 substrates despite the very large lattice mismatch between the film and the substrate. The epitaxial BiScO3 films

Piezoelectric Response of Nanoscale PbTiO3 in Composite PbTiO3-CoFe2O4 Epitaxial Films

August 15, 2008

Author(s)

Igor Levin, Tan Zhuopeng, Alexander Roytburd, Katyayani Seal, Brian Rodriguez, Stephen Jesse, Sergei Kalinin, Art Baddorf

Piezoelectric properties of PbTiO3 in 1/3PbTiO3-2/3CoFe2O4 transverse epitaxial nanostructures on differently oriented SrTiO3 were analyzed using conventional and switching-spectroscopy piezoelectric force microscopy. The results confirmed that the

Nature of Transition Layers at the SiO 2 /SiC Interface

July 14, 2008

Author(s)

T Zheleva, Aivars Lelis, G Duscher, F Liu, Igor Levin, M Das

Electrical performance of SiC-based microelectronic devices is strongly affected by the densities of interfacial traps introduced by the chemical and structural changes at the SiO2/SiC interfaces during processing. We analyzed the structure and chemistry

Crystal Structure, Stoichiometry, and Dielectric Relaxation in Bi 3.32 Nb 7.09 O 22.7 and Structurally Related Ternary Phases

April 17, 2008

Author(s)

I E. Grey, Terrell A. Vanderah, W G. Mumme, Robert S. Roth, Jorge T. Guzman, Juan C. Nino, Igor Levin

Ceramic materials which exhibit high relative dielectric permittivities and are processible at temperatures in the 1000 C to 1200 C range are of interest for embedded elements such as capacitor, resonators, and filters. Complex titanates, niobates, and

Growth of Silicon Carbide Nanowires by a Microwave Heating-Assisted Physical Vapor Transport Using Group VIII Metal Catalysts

November 13, 2007

Author(s)

Siddarth Sundaresan, Albert Davydov, Mark D. Vaudin, Igor Levin, James E. Maslar, Yong-lai Tian, M V. Rao

SiC nanowires are grown by a novel catalyst-assisted sublimation-sandwich (SS) method. This involves microwave heating-assisted physical vapor transport from a source 4H-SiC wafer to a closely positioned substrate 4H-SiC wafer. The substrate wafer is

Kinetics Studies of the Interfacial Reactions of the Ba 2 Ycu 3 O 6+x Superconductor With CeO 2 Buffer

October 16, 2007

Author(s)

Lawrence P. Cook, Winnie K. Wong-Ng, Z Yang, Peter K. Schenck, Igor Levin, Julia Frank

Interfacial reactions between the Ba2YCu3O6+x superconductor and the CeO2 buffer layer employed in coated conductors have been modeled experimentally by investigating the kinetics of the reaction between Ba2YCu3O6+x and CeO2. At 810 C and pO2 = 100 Pa, the

Thermodynamic Aspects of Epitaxial Self-Assembly and Magnetoelectric Response in Multiferroic Nanostructures

August 26, 2007

Author(s)

Julia Slutsker, Zhuopeng Tan, Alexander L. Roytburd, Igor Levin

A thermodynamic approach has been used to describe the formation and magnetoelectric response of composite multiferroic films. Experimental and theoretical results that address the origins of different phase morphologies in epitaxial spinel-perovskite

Accommodation of Transformation Strains in Transverse Multiferroic Nanostructures CoFe 2 O 4- PbTiO 3

August 16, 2007

Author(s)

Igor Levin, Julia Slutsker, J Li, Z Tan, Alexander L. Roytburd

Variable-temperature X-ray diffraction was used to investigate the internal strains that arise from a ferroelectric phase transition in self-assembled multiferroic nanostructures CoFe2O4-PbTiO3 on (001) SrTiO3. The constraints from CoFe2O4 suppressed the c

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