bluuebunny/crossref_metadata_2025_split huggingface dataset:
Switching from Homogeneous to Localized Corrosion in Stainless-Type Amorphous and Nano-Crystalline Steels
Authors: Renner Frank Uwe , Duarte Maria Jazmin 
Published: February 2020

Amorphous stainless-type steels with high Cr content provide next to some applications as corrosion protective coatings an interesting playground for fundamental studies of electrochemical corrosion behavior (1-4). Starting from an ultimately homogeneous glassy version, partially and fully nanocrystalline states with large elemental heterogeneity depending on the crystallization can be derived by simple heat treatments (1,2). The amorphous materials Fe65-xCrxMo14C15B6show relative low passive currents which significantly increase after partial crystallization owing in part to a related nano-scaled roughness of the passive films (Fig.1). For low-Cr contents we have as well observed a clear switch from the typical homogeneous corrosion of these alloys to a clearly localized attack. We will discuss this phenomenon in the light of atom probe tomography (Fig.2), microscopy, and electrochemical measurements.
1. M. J. Duarte, A. Kostka, J. A. Jimenez, P. Choi, J. Klemm, D. Crespo, D. Raabe, F. U. Renner, Crystallization, phase evolution, and corrosion of Fe-based metallic glasses: an atomic-scale structural and chemical characterization study, 2014, Acta Materialia 71 (2014), 20-30.
2. M.J. Duarte, J. Klemm, S. O. Klemm, S. Borodin, K. Mayrhofer, M. Stratmann, A.H. Romero, D. Crespo, J. Serrano, P. Choi, D. Raabe, F. U. Renner, Element-Resolved Corrosion Analysis of Stainless-Type Glass-Forming Steels, Science 341 (2013), 372-376.
3. M. Madinehei, P. Bruna, M.J. Duarte, S. J. A. Figueroa, E. J. Lede, J. Lengsfeld, F. U. Renner, E.Pineda, Glass-formation and corrosion properties of Fe-Cr-Mo-C-B glassy ribbons with low Cr content, J. Alloy. Comp. 615 (2014), 128 - 131.
4. J. Klemm, M.J. Duarte, S. O. Klemm, P.Choi, K.J.J. Mayrhofer, F.U. Renner, Multi-element-resolved electrochemical corrosion analysis. I. Dissolution behavior and passivity of amorphous Fe50Cr15Mo14C15B6, Corrosion Science 89 (2014), 59-68.

Figure 1
Corrosion Product Structures of Steel Samples Exposed to Amine Solutions Used for H2s Removal.
Authors: Alpuche-Aviles Mario A , Waite Scott , Malkiewich Ryan , Parajuli Suman , Muñoz Maria , Chhetri Pushpa 
Published: February 2020

We present our results on the corrosion effects of heat stable salts (HSS), i.e., amine salts and amino acids that occur during removal of H2S from petroleum and natural gas with alkanolamines. The salts include heat stable salts and amine degradation products. Corrosion was measured using coupon weight loss in liquid and vapor phases in stirred solutions that model amine plant environment (e.g., in refinery systems). We have developed a chamber that enables exposure of samples to the gas and liquid phases of amine solutions. At increasing concentration of HSS the corrosion products show well defined structures in the nanometer scale in the solutions exposed to the liquid phase. However, this was not observed in the vapor phase. Overall, the corrosion products include amorphous, columnar and disk-shaped structures depending on the exposure conditions. We discuss the implication of the products formed on the corrosion mechanism under this environment and we propose that the substrates become passivated and that localized corrosion takes place under the conditions of our study that mimic the HSS buildup in a plant.
The corrosion products were characterized by scanning electron microscopy and X-ray powder diffraction. We report our findings for the corrosion rate measured in amine solutions with progressive additions of H2S and additional amine salts. In summary, we found the weight loss to be significantly different for samples exposed to the liquid phase and to the vapor phase: all of our liquid samples had corrosion rates < 10 mils per year (mpy), while the samples in the head space corroded at ³ 10 mpy. Our measurements were carried out in a closed environment with the liquid composition under control. For all of our experiments, the solution was purged with N2 and then H2S was dosed to achieve a concentration of 0.01 M/M of H2S/MDEA . The corrosion rates in the head space do follow a trend with respect to the composition in the liquid. Most notably, the corrosion rates in both liquid and gas increase when bicine is added. In addition the corrosion rate in both liquid and gas phases increased when the HSS level increased from 1.4 to 5%. This suggests that some of the heat stable salts are present in the head space, possibly from partitioning via vaporization or splashing into the head space.
Modulating the Anionic-Electronic Transport Kinetics to Trigger Memristance for Resistive Switching Non-Volatile Memories: New Materials, Structering and Methods
Authors: Rupp Jennifer L. M. , Messerschmitt Felix , Schweiger Sebastian , Schmitt Rafael , Kubicek Markus 
Published: February 2020

Bipolar resistive switches were recently proposed as a new class of non-volatile switches capable of reading, writing and erasing memory information by switching non-linearly between low- and high-resistance values by application of mV voltage pulses in the ns range. In the last years, resistive switching has been reported for various classes of materials ranging from sulfides to oxides. Despite their promises oxide-based resistive switches are rarely connected in their diffusion kinetics and constants to the memristive device performance characteristics under bias. In particular, models to describe the mixed anionic-electronic defect contributions for two-carrier systems are missing; this difficults the material selection criteria for best performing devices beyond classic gate oxide selection. Firstly, we report on how to probe carrier diffusion characteristics and memristance for mixed anionic-electronic resistive switches and their oxide materials for the newly proposed Memristor-based Cotrell analysis. For this, we fabricated 2-terminal Pt|SrTiO3-δ|Pt cross-bar array structures as a model system in terms of its mixed defects which show stable and reproducible resistive switching. Secondly, new material engineering of oxides are discussed to control resistive switching device properties like retention, Ron/Roff ratios and power consumption by "interfacial strain engineering of mixed conducting oxide" is reported. Lattice strain engineering using heterostructures at internal interfaces can be used to tune material properties in micro-dots as new resistive switching archiectures far beyond the change accessible by doping. We exemplify the switching characteristics based on either comprsively or tensily strained Gd0.1Ce0.9O2-x heterolayers by Er2O3 or Sm2O3 monolayer modulation, respectively. Thirdly, the role of grain boundaries is discussed for epitaxially and nm-roughness grown LaFeO3 thin film resistive switches with controlled defect levels. We compliment classic resistive switching tests characterizing the near order Raman vibrational (ionic bonding), direct and non-linear optic spectroscopy techniques (electronic contributions).
(Keynote) Nanoscale Memories: What Does Physics Have to Say?
Authors: Zhirnov Victor V. , Meade R , Pandey S. C. , Sandhu G 
Published: February 2020

Device scaling and energy consumption during computation has become a matter of strategic importance for future information technologies. The central question addressed in this talk is: What is the smallest volume of matter needed for a memory element? A generic physics-based abstraction for memory devices will be introduced and applied to several baseline memory technologies. The scaling limit of electron-based devices is~5-7 nm due to quantum-mechanical tunneling. Smaller devices can be made, if information-bearing particles are used whose mass is greater than the mass of an electron. Therefore the new principles for devices, scalable to ~1 nm, could be ‘moving atoms’ instead of ‘moving electrons’.
Theoretical feasibility of the 1-nm devices will be justified based on electrical properties of the few-atom systems. Next, thermal properties of atomic contacts and devices such as nanoionic switch/ReRAM memory cell will be discussed to provide an insight whether such small structure could have sufficient thermal stability for reliable operation.
An important task for sub-10 nm nanodevices is recognition of the fundamental role of ‘defects’ that should not be treated as imperfections but instead as controllable entities. The materials nonstoichiometry due to point defects plays a key role in the electronic properties of many materials, for example in metal oxides. Due to these nonstoichiometric defects, the materials often behave as doped semiconductors. In fact, these materials form a special class, sometimes called ‘chemiconductors’.
In addition to solid-state nanoionic devices such as ReRAM) concepts of ‘fluid nanoelectronics’ are proposed that utilize liquid media, which may offer a new promising path to replace the foundation of today’s computing technologies. Examples include nanoionic devices based on electrolyte-filled nanochannels. In principle, such structures might be used to make devices scalable to ~1 nm or below.
Recently there have been suggestions from research that the physical limits of semiconductor technology may in fact be overcome by borrowing from synthetic biology principles. For example, it has recently been shown that DNA can be used to achieve storage densities that cannot be approached by any known solid-state technology. This lecture will examine how one might develop a technology in the semiconductor context that would open up DNA memory to widespread applications.
Lead Free Metal-Ferroelectric-Insulator-Semiconductor Devices for Non-Volatile Memory Appliactions
Authors: Medwal Rohit , Gupta Surbhi , Pavunny Shojan P. , Katiyar Rajesh K. , Thomas Reji , Katiyar Ram S. 
Published: February 2020

The polarization bistability of the ferroelectric material offers the possibility to develop dense, energy efficient, fast and non volatile ferroelctric random access memory (FeRAM) with long retention and high endurance, as a promising replacement to both DRAM and Flash for the continued scaling. With this motivation, metal-ferroelectric-insulator-semiconductor (MFIS) structures were fabricated on p-Si <100> semiconductor substrate, by first depositing a 6 nm thick amorphous DyScO3 high-k insulator layer using metal organic chemical vapor deposition (MOCVD), followed by a 265 nm thick polycrystalline BiFeO3 (BFO) ferroelectric layer employing radio frequency (RF) sputtering, and finally a 40 nm thick platinum metal layer by DC magnetron sputtering. Electrical properties of the developed MFIS (Pt/BiFeO3/DyScO3/SiOx/Si) stacks were characterized as a function of thermal agitation (200 K to 400 K) to evaluate their device performance. Fat hysteresis loop was observed in the frequency dependent (1 kHz-1 MHz) capacitance-voltage (C-V) measurement with a memory window (ΔVFB) of 0.8 V at an exceptionally very low sweep voltage of ± 2 V. The memory window increased to 2.2 V as the sweep voltage was raised to ± 4 V and beyond up to ± 8 V, indicating a highly stable device. Low leakage current (1.2 μA/cm2 at 4 V) and excellent data retention characteristics with distinguishable high and low capacitance values over the long time period of 106 sec, revealed strong charge storage potential of the fabricated device architecture. The non-linear hysteretic J-E curves of the MFIS structure were also investigated in detail as a function of temperature to understand the device reliability and the charge transport mechanisms. Piezoelectric force microscopy (PFM) and P-E hysteresis loop (domains reversal) studies were carried out to confirm the ferroelectric nature of the polycrystalline BFO thin films. The encouraging results achieved reveals that Pt/BiFeO3/DyScO3/SiOx/Si MFIS device architecture is a promising one for realization of FeRAM devices.
(Invited) Low Power Stt-Mram and Its Application to Normally-Off Processor
Authors: Shimomura Naoharu , Saida Daisuke , Daibou Tadaomi , Kato Yushi , Kamata Chikayoshi , Kashiwada Saori , Osawa Yuichi , Noguchi Hiroki , Ito Junichi , Fujita Shinobu , Yoda Hiroaki 
Published: February 2020

Reduction of the power consumption of mobile electronic devices is one of the principal issues in current and future electronics technology. In particular, reducing the power consumption of the processor is critical because it increases as the processor’s performance improves.
Normally-off computing is one of the solutions. Standby power of a cache memory while the device power is on but the memory is idle accounts for a large proportion of the processor’s power consumption, which can be eliminated by shutting down the cache memory during the idle time and turning it on instantly when the memory becomes active. The key technology for the normally-off processor to reduce power effectively is a fast, low-power, non-volatile memory for the cache memory to replace the current SRAM cache memory.
Among the various non-volatile memories, Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) is the most promising candidate for the cache memory of the normally-off processor because of its potential performance in terms of fast switching and scalability. A magnetic tunnel junction (MTJ) storage element having perpendicular magnetization (p-MTJ) reduces the writing current of the STT-MRAM, which enables scaling of the STT-MRAM.
However, for power saving of the normally-off processor, small write current and short write pulse duration time must be achieved simultaneously. In other words, write charge, which is write current multiplied by write pulse width, is a key parameter for power saving. Toshiba demonstrated STT switching of the p-MTJ with write charge of 90 fC whose write pulse width was 1 ns and write current was 90 uA. Simulation of the processor’s power consumption with this STT MRAM showed good power saving.
Landau–Lifshitz–Gilbert (LLG) micromagnetic simulation of spin-transfer torque shows that a coherent precession of the spin plays an important role for fast switching of the p-MTJ. Initially, when the write current is applied to the p-MTJ, each spin precesses independently and the spin stays in the initial direction. It corresponds to incubation delay time. Immediately after the precession of each spin is synchronized and rotates coherently, switching of the spin begins. Therefore, the coherency of the spin precession needs to be controlled for further improvement of the fast switching of the p-MTJ.
A part of this work was supported by NEDO.
(Invited) Mechanism Study of Reversible Resistivity Change in Oxide Thin Film
Authors: Hong Seungbum , Chang Seo Hyoung , Phatak Charudatta , Magyari-Kope Blanka , Nishi Yoshio , Chattopadhyay Soma , Kim Jung Ho 
Published: February 2020

The field of applied physics is driven by the need to understand materials structure and electronic properties with the ultimate goal of harnessing them in functional devices such as nonvolatile memories. One needs to understand the mechanism, which dictates the behavior of the charged defects and electrons under external stimuli such as electrostatic potential, thermal gradient and photons, to obtain a more microscopic understanding of the system. Then, one arrives at a predictive description of designing functional devices.
In the first part of the talk, we report the x-ray-induced reversible resistance change in 40-nm-thick TiO2 films sandwiched by Pt top and bottom electrodes, and propose the physical mechanism behind the emergent phenomenon. Our findings indicate that there exists a photovoltaic-like effect, which modulates the resistance reversibly by a few orders of magnitude, depending on the intensity of impinging x-rays. We found that this effect, combined with the x-ray irradiation induced phase transition confirmed by transmission electron microscopy, triggers a non-volatile reversible resistance change. Understanding x-ray-controlled reversible resistance changes can provide possibilities to control initial resistance states of functional materials, which could be useful for future nonvolatile memories.
In the second part, we cover the investigation of Ta2O5 powder and oxygen deficient thin films using synchrotron x-ray studies at the Advanced Photon Source, combining x-ray diffraction, extended x-ray absorption fine structure (EXAFS) and resonant x-ray scattering spectroscopy (RIXS) and Ab initio band structure calculations. Ta-based resistive switching devices have been extensively investigated due to their fast switching and reliable endurance among other materials. Despite extensive recent interests, however, there is still lack of fundamental understanding of electronic structure and local structure of the Ta-based device. Oxygen vacancies play essential roles in the electric functionality of resistive switching devices, which is based on the formation and rupture of conducting paths within the insulating matrix. We found that there are strong correlations among oxygen vacancy number and positions and energy gaps. Ab initio band structure calculations successfully explain the evolution of the electronic excitation spectrum as a function of oxygen vacancy number and positions and importantly provide a predictive description of the oxygen deficient Ta oxide that may improve the desired performance based on atomic level design rather than the traditional trial-error methods.
(Invited) CH3NH3PbI3 Perovskite Solar Cells on Inorganic Materials: CuSCN and Crystal Silicon
Authors: Ito Seigo 
Published: February 2020

Organo-lead halide perovskites have attracted much attention for solar cell applications due to their unique optical and electrical properties. With either low-temperature solution processing or vacuum evaporation, the overall conversion efficiencies of perovskite solar cells with organic hole-transporting material were quickly improved to over 20% during the last 3 years. However, the organic hole-transporting materials used are normally quite expensive due to complicated synthetic procedure or high-purity requirement. Here, we demonstrate the application of an effective and cheap inorganic p-type hole-transporting material, copper thiocyanate (CuSCN), on lead halide perovskite-based devices. With low-temperature solution-process deposition method, a power conversion efficiency of 12.4% was achieved under full sun illumination. This work represents a well-defined cell configuration with optimized perovskite morphology by two times of lead iodide deposition, and opens the door for integration of a class of abundant and inexpensive material for photovoltaic application. Moreover, in the conference presentation, stability study of perovskite crystal and tandem solar cells (perovskite solar cells on home-made silicon solar cells) will be presented.
Reduction of Graphene Oxide through Intense Pulsed Light Towards Transparent Conductive Coating Applications
Authors: Draper Gabriel , Dharamsena Ruchira , Lavery Brandon , Druffel Thad 
Published: February 2020

This work studies the capabilities and conditions for reduction of solution processed graphene oxide films through an Intense Pulse Light process towards flexible and additive deposition of transparent conductive coatings. The film deposition and reduction processes occurred at room temperature without need for any vacuum processing. The reduction for the graphene oxide is explored at different energy densities and the reduced graphene oxide’s conductivity displayed an increasing trend with increased Intense Pulsed Light processing. Characterization techniques of Raman spectroscopy, UV-Visible spectroscopy, X-Ray Diffraction, and the four point probe method were employed for analysis. Through the Intense Pulsed Light process, the characteristic Raman peak of graphene (2D) emerged. When compared to the graphite (G) peak, the 2D/G ratio showed a general trend of increasing with higher energy inputs, going from 1.06 at 256 Jcm-2 and 1.76 at 1723 Jcm-2. The defects (D peak) to G peak ratio, D/G, displayed a decreasing trend with increasing energy input going from 1 to .89 at 256 Jcm-2 and .38 at 1723 Jcm-2, suggesting that the Intense Pulsed Light process “heals” the films, in addition to the reduction.
Renewable Energy Forecast Using Machine Learning
Authors: Shao Ingrid , Lu Siyuan , Hamann Hendrik F. 
Published: February 2020

Renewable energy forecasting becomes increasingly important as the contribution of solar/wind power production to the electrical power grid constantly increases.[1] Significant improvement in forecasting accuracy has been demonstrated by developing more sophisticated solar irradiance forecasting models using statistics and/or numerical weather predictions.[2] In this presentation, we report the development of a machine-learning based multi-model blending approach for statistically combing multiple meteorological models for improving the accuracy of solar power forecast. The system leverages upon multiple existing physical models for prediction including numerous atmospheric and cloud prediction models based on sky camera and satellite imagery as well as numerical weather prediction (NWP) products. Fig 1 shows an architectural view of this forecast system. Results using the system show over 30% improvement in solar irradiance/power forecast accuracy compared to forecast based on the best individual model.[3] A typical forecast time series plot is shown in Fig 2 together with measurement data and power from clear sky conditions. We also demonstrated that in addition to the parameters to be predicted (such as solar irradiance and power), including additional state parameters which collectively define a weather situation as machine learning input provides further enhanced accuracy for the machine learning result. This methodology has also been applied to wind power generation forecast and similar improvement in accuracy has been demonstrated.
The work is partially supported by Department of Energy SunShot Initiative contract #DE-EE0006017.
[1] R. Margolis,C. Coggeshall, J. Zuboy, “Integration of solar into the U.S. electric power system”, Chap 6 in SunShot Vision Study, US Department of Energy, http://energy.gov/eere/sunshot/sunshot-vision-study(2012)
[2] M. Dagne, M. David, P. Lauret, J. Boland, and N. Schmutz, “Review of Solar Irradiance Forecasting Methods and a Proposition for Small-Scale Insular Grids”, Renewable and Sustainable Energy Reviews, 27, p65 (2013)
[3] S. Lu, Y. Hwang, I. Khabibrakhmanov, H. Dang, T. van Kessel, F. Marianno, X. Shao, H. F. Hamann, “Machine Learning Based Multi-Model Blending for Enhancing Renewable Energy Forecasting”, American Meteorological Society Annual Meeting Abstract J6.4, Phoenix, AZ, January 4-8, 2015.

Figure 1