Superconducting weak link generated on a linear array of substrate steps in ultrathin films of YBa2Cu3O7-x

We have studied a three-unit-cell-thick YBa2Cu3O7-x (YBCO) superconducting film grown on a slightly vicinal SrTiO3 substrate that was polished from the (001) plane by a small miscut angle (less than 0.5 degrees). This produced, on its surface, a linear array of single-unit-cell-height steps with a period larger than 40 nm. A characteristic fault, with a displacement corresponding to one-third of the c-axis length of YBCO, is generated in the film on each substrate step, as observed by atomic force microscopy. Transport measurements with current flows parallel and perpendicular to the fault show that the fault serves as a superconducting weak link, as well as a unique one-dimensional flux-pinning center in an applied magnetic field. In addition, a characteristic fine structure is found in the flux-flow resistivity as a function of magnetic field, the origin of which may be ascribed to a matching effect between the periodically aligned faults and the flux lattice.Comment: 5 pages, 3 figures. Phys. Rev. B (in press

メゾアリールサブポルフィリンの化学

京都大学0048新制・課程博士博士(理学)甲第17941号理博第3911号新制||理||1564(附属図書館)30771京都大学大学院理学研究科化学専攻(主査)教授 大須賀 篤弘, 教授 丸岡 啓二, 教授 時任 宣博学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

You Can\u27t Stop The Beat Bringing Musical Theatre To Underprivileged Youth

In an age of standardized testing and quality-controlled classrooms, teachers have lost the freedom to integrate imagination and creativity in their lessons, ultimately cheating today’s youth. In the classroom, students no longer have the outlets that transport them from the harsh realities of life. This thesis is an attempt to provide a venue for the Orange County Public School System that will engage the imaginations of under-represented or underprivileged students. The thesis will chronicle the development of a script with the intent of producing it in Title I elementary schools located in lower socio-economic areas of Orlando, Florida. The script will be based on Hans Christian Anderson’s fairy tale “The Ugly Duckling.” The final product will be a musical theatre piece to take into the school system to be performed by the students. The body of the thesis will contain my prior experiences of bringing musical theatre to underprivileged youth. The document will also include chapters detailing the process of creating the script and composing the music. Research will determine the socio-economic challenges prevalent in the under-represented cultures in the urban schools of Orlando. Finally, the thesis will contain a section of the actual script and will conclude with a chapter summarizing the reactions to the first reading of the pla

Desorption dynamics of deuterium molecules from the Si(100)-(3×1) dideuteride surface

We measured polar angle ()-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3×1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of 0.25 eV, which is mostly independent of the desorption angles for 0°30°. The observed desorption dynamics of deuterium was discussed along the principle of detailed balance to predict their adsorption dynamics onto the monohydride Si surface

Operation analysis of resistive switching of CBRAM using in-situ TEM

Resistive random access memories (ReRAMs) have great potential as a candidate for next-generation nonvolatile memories for the high speed, high density storage per cost [1] and their ability to the neural network devices. In order to analyze the reliability of ReRAMs and to find out the origin of the failures, it indispensable to understand the resistive switching mechanism. Since the transmission electron microscopy (TEM) provides a high resolution images of the nanostructure, in-situ TEM should be a powerful tool for the analysis. In our in-situ TEM system [2, 3], repeatable switching characteristics, are achieved together with clear images of formation and rupture of conductive filaments corresponding to the low and high resistance states. In this work, we used several kinds of Cu-based ReRAM (CBRAM: Conductive Bridge RAM). TEM samples are fabricated by two methods. One is an ion-shadow method [4, 5], which is an ion milling technique with carbon mask particles. The other is FIB that is a conventional technique to make a sample observable in TEM. Almost the same characteristics as those measured at the outside of TEM by the use of real ReRAM cells are achieved in TEM by the both method. Fig. 1 shows an example of I-V switching characteristics of Cu-Te based ReRAM [6, 7] and the corresponding TEM images [2, 3]. It was clearly shown that a dark spot corresponding to a conductive filament appeared by SET and erased after RESET. These resistive switching characteristics by I-V sweep were reproducible at least 60 cycles in TEM. In addition, SET/RESET pulse operation more than 100k times are confirmed during TEM observation as shown in Fig. 2. These results clearly indicate that the in-situ TEM will be a powerful tool to guarantee the reliability of ReRAMs. Please click Additional Files below to see the full abstract

Nanoscale Switching and Degradation of Resistive Random Access Memory Studied by In Situ Electron Microscopy

The metal-filament-type resistive random access memories (ReRAMs) with copper were investigated from the point of view of dynamical microstructure evolution in the repetitive switching operations using in situ transmission electron microscopy (in situ TEM). Through a series of experiments for uncovered solid electrolyte films, stacked devices, and nanofabricated cells, formation and erasure of the copper filaments and deposits were confirmed. The behavior of the filament and deposit depended on the switching condition and history. Based on these in situ TEM results, the switching schematics and the degradation process were discussed