Tip Induced Surface Defect migration and Conductivity Studies in Tetragonal, Rhombohedral and Mixed-Phase epitaxial BiFeO3 Thin Films

MRS Advances ◽  
2018 ◽  
Vol 3 (44) ◽  
pp. 2713-2718 ◽  
Author(s):  
M M Saj Mohan ◽  
M V Sreenath ◽  
Ranjith Ramadurai
Keyword(s):  
Room Temperature ◽  
Surface Defect ◽  
Bismuth Ferrite ◽  
Rhombohedral Phase ◽  
Mixed Phase ◽  
Room Temperature Resistivity ◽  
Defect Migration ◽  
Nano Scale ◽  
Atomic Force ◽  
Pure Phases

AbstractBiFeO3 (BFO) is the most studied room temperature multiferroic compound. In this work we demonstrate a template assisted growth process through which the growth strain is controlled to achieve required phase of BFO. Growth of (∼20nm) fully strained tetragonal (T), rhombohedral (R) and mixed phase of T and R of Bismuth ferrite (BiFeO3) was achieved by varying the thickness of the template layer. The different phases were confirmed by using high resolution x-ray diffractions studies. The conductivity map of all the three phases were carried out using an atomic force microscope operating in conductive mode. Tip induced surface defect migration within a given grain was observed in pure phases and the conductivity map confirmed the same. The room temperature resistivity is found to be decreasing systematically from 1.1×106 Ωm , 935×105 Ωm and 1.16×104 Ωm respectively for tetragonal, mixed phase and rhombohedral phase BFO. In the case of mixed phase both the nano- scale and macroscopic leakage current studies show low conductivity, which could be due to the increased pinning sites that increases the energy barrier for the defect migration. The local nano-scale measurements and conductivity mapping corroborates well with the macroscopic studies.

Experimental and Simulation Research on Influence of Temperature on Nano-Scratching Process of Silicon Wafer

2007 ◽  
Vol 329 ◽  
pp. 379-384 ◽  
Author(s):  
H. Okabe ◽  
T. Tsumura ◽  
Jun Shimizu ◽  
Li Bo Zhou ◽  
Hiroshi Eda
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Surface Defect ◽  
Atomic Interaction ◽  
Simulation Research ◽  
Atomic Force ◽  
Influence Of Temperature On ◽  
Grinding Conditions ◽  
Dynamics Method ◽  
Si Wafer

This study aims to clarify the interaction between Si wafer and individual diamond abrasives in grinding at nanometer level and to estimate the grinding conditions for minimizing the surface defect. This paper reports on the results obtained through nano-scratching experiments in vacuum by an atomic force microscope (AFM) and simulations by using the molecular dynamics method by applying Tersoff potential for Si-Si atomic interaction under room and high temperature, respectively, to examine the influence of the grinding heat on the materials removal process. As a result, it was proven that the scratch groove under high temperature becomes deeper than that under room temperature from the experiments, and it was also observed that the formation of the amorphous phase around the scratch groove under high temperature becomes a little bit larger than that under room temperature from the simulations.

scholarly journals Characterization of Silver Oxide Films Formed by Reactive RF Sputtering at Different Substrate Temperatures

ISRN Optics ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
P. Narayana Reddy ◽  
M. Hari Prasad Reddy ◽  
J. F. Pierson ◽  
S. Uthanna
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Silver Oxide ◽  
Rf Sputtering ◽  
Spherical Shape ◽  
Rf Magnetron Sputtering ◽  
Mixed Phase ◽  
Silicon Substrates ◽  
Atomic Force ◽  
Silver Target

Silver oxide (A2O) films were deposited on glass and silicon substrates held at temperatures in the range 303–473 K by reactive RF magnetron sputtering of silver target. The films formed at room temperature were single phase Ag2O with polycrystalline in nature, while those deposited at 373 K were improved in the crystallinity. The films deposited at 423 K were mixed phase of Ag2O and Ag. Atomic force micrographs of the films formed at room temperature were of spherical shape grains with size of 85 nm, whereas those deposited at 473 K were with enhanced grain size of 215 nm with pyramidal shape. Electrical resistivity of the single phase films formed at room temperature was 5.2 × 10−3 Ωcm and that of mixed phase was 4.2 × 10−4 Ωcm. Optical band gap of single phase films increased from 2.05 to 2.13 eV with the increase of substrate temperature from 303 to 373 K, while in mixed phase films it was 1.92 eV.

Vanadium sesquioxide (V2O3)-based semiconducting temperature sensitive resistors for uncooled microbolometers

2017 ◽  
Vol 31 (13) ◽  
pp. 1750145 ◽  
Author(s):  
Mohamed Abdel-Rahman ◽  
Mohammad Alduraibi ◽  
Muhammad Fakhar Zia ◽  
Esme Bahidra ◽  
Amr Alasaad
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Temperature Sensitive ◽  
Room Temperature Resistivity ◽  
Force Microscopy ◽  
Atomic Force ◽  
Vanadium Sesquioxide ◽  
Surface Morphologies ◽  
High Temperature Sensitivity ◽  
Temperature Resistivity

This paper reports on a semiconducting resistor material based on vanadium sesquioxide (V2O3) with electrical resistivity and temperature coefficient of resistance (TCR) appropriate for microbolometer applications. In this work, V2O3-based semiconducting resistor material was synthesized and electrically characterized. The developed material was prepared by annealing, in O2 and N2 atmospheres, a cascaded multilayer structure composed of V2O3 (10 nm) and V (5 nm) room temperature sputter coated thin films. The developed 55 nm thin film microbolometer resistor material possessed high temperature sensitivity from 20[Formula: see text]C to 45[Formula: see text]C with a TCR of −3.68%/[Formula: see text]C and room temperature resistivity of 0.57 [Formula: see text] for O2 annealed samples and a TCR of −3.72%/[Formula: see text]C and room temperature resistivity of 0.72 [Formula: see text] for N2 annealed samples. The surface morphologies of the synthesized thin films were studied using atomic force microscopy showing no significant post-growth annealing effect on the smoothness of the samples surfaces.

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

Influence of Modulation Wavelength Induced Order on the Physical Properties of Nb/Rare Earth Superlattices

1984 ◽  
Vol 37 ◽  
Author(s):  
L. H. Greene ◽  
W. L. Feldmann ◽  
J. M. Rowell ◽  
B. Batlogg ◽  
R. Hull ◽  
...  
Keyword(s):  
Rare Earth ◽  
Room Temperature ◽  
Room Temperature Resistivity ◽  
Residual Resistance ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Residual Resistance Ratio ◽  
Temperature Resistivity ◽  
Modulation Wavelength

AbstractWe report the observation of a higher degree of preferred crystalline orientation in Nb/rare earth superlattices for modulation wavelengths in the range of 200 Å to 500 Å than that exhibited by single component films. All films and multilayers are sputter deposited onto room temperature sapphire substrates. Electronic transport measurements also show that the residual resistance ratio is higher and the room temperature resistivity is lower than for multilayers of either greater or lower periodicities. Transmission electron micrographs (TEM) showing excellent layering, grain size comparable to the layer thickness, and evidence of some degree of epitaxy are presented.

The Study on Microstructural and Optical Properties of Nanocrystalline Germanium Films

2010 ◽  
Vol 663-665 ◽  
pp. 324-327
Author(s):  
Chao Song ◽  
Rui Huang
Keyword(s):  
Multilayer Structure ◽  
Room Temperature ◽  
Multilayer Film ◽  
Volume Fraction ◽  
Raman Scattering Spectroscopy ◽  
Force Microscopy ◽  
Room Temperature Photoluminescence ◽  
Atomic Force ◽  
Lower Volume Fraction ◽  
Lower Volume

The germanium film and Ge/Si multilayer structure were fabricated by magnetron sputtering technique on silicon substrate at temperatures of 500°C. Raman scattering spectroscopy measurements reveal that the nanocrystalline Ge occurs in both kinds of samples. Furthermore, from the atomic force microscopy (AFM) results, it is found that the grain size as well as spatially ordering distribution of the nc-Ge can be modulated by the Ge/Si multilayer structure. The room temperature photoluminescence was also observed in the samples. However, compared with that from the nc-Ge film, the intensity of PL from the nc-Ge/a-Si multilayer film becomes weaker, which is attributed to its lower volume fraction of crystallized component.

scholarly journals Computational Intelligence Approach for Estimating Superconducting Transition Temperature of Disordered MgB2Superconductors Using Room Temperature Resistivity

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Taoreed O. Owolabi ◽  
Kabiru O. Akande ◽  
Sunday O. Olatunji
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Room Temperature ◽  
Optimization Technique ◽  
Support Vector ◽  
Measuring Instruments ◽  
Room Temperature Resistivity ◽  
Superconducting Transition ◽  
Experimental Values ◽  
Temperature Resistivity

Doping and fabrication conditions bring about disorder in MgB2superconductor and further influence its room temperature resistivity as well as its superconducting transition temperature (TC). Existence of a model that directly estimatesTCof any doped MgB2superconductor from the room temperature resistivity would have immense significance since room temperature resistivity is easily measured using conventional resistivity measuring instrument and the experimental measurement ofTCwastes valuable resources and is confined to low temperature regime. This work develops a model, superconducting transition temperature estimator (STTE), that directly estimatesTCof disordered MgB2superconductors using room temperature resistivity as input to the model. STTE was developed through training and testing support vector regression (SVR) with ten experimental values of room temperature resistivity and their correspondingTCusing the best performance parameters obtained through test-set cross validation optimization technique. The developed STTE was used to estimateTCof different disordered MgB2superconductors and the obtained results show excellent agreement with the reported experimental data. STTE can therefore be incorporated into resistivity measuring instruments for quick and direct estimation ofTCof disordered MgB2superconductors with high degree of accuracy.

Hydrogen Transport and Hydrogen-Assisted Cracking in SUS304 Stainless Steel During Deformation at Low Temperatures

2015 ◽  
Author(s):  
Lin Zhang ◽  
Bai An ◽  
Takashi Iijima ◽  
Chris San Marchi ◽  
Brian Somerday
Keyword(s):  
Stainless Steel ◽  
Hydrogen Embrittlement ◽  
Room Temperature ◽  
Hydrogen Release ◽  
Hydrogen Transport ◽  
Force Microscopy ◽  
Atomic Force ◽  
Strain Induced Martensite ◽  
Hydrogen Assisted Cracking ◽  
Slip Planes

The behaviors of hydrogen transport and hydrogen-assisted cracking in hydrogen-precharged SUS304 austenitic stainless steel sheets in a temperature range from 177 to 298 K are investigated by a combined tensile and hydrogen release experiment as well as magnetic force microscopy (MFM) based on atomic force microscopy (AFM). It is observed that the hydrogen embrittlement increases with decreasing temperature, reaches a maximum at around 218 K, and then decreases with further temperature decrease. The hydrogen release rate increases with increasing strain until fracture at room temperature but remains near zero level at and below 218 K except for some small distinct release peaks. The MFM observations reveal that fracture occurs at phase boundaries along slip planes at room temperature and twin boundaries at 218 K. The role of strain-induced martensite in the hydrogen transport and hydrogen embrittlement is discussed.

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