Substrate effect on the temperature coefficient of resistance of La0.7Ca0.3MnO3 thin films prepared by metal organic deposition

Epitaxial La_0.7Ca_0.3MnO₃ (LCMO) thin films were successfully prepared by the metal-organic deposition process on various (001) single-crystal substrates: MgO, LaAlO₃ (LAO), SrTiO₃ (STO), and (LaAlO₃)_0.3-(SrAlTaO₆)_0.7 (LSAT). The crystallinity and the epitaxial growth of the LCMO films were characterized by X-ray diffraction (θ − 2θ scans and pole-figure analysis). The temperature dependence of the resistance of the LCMO/LSAT, LCMO/STO and LCMO/LAO films exhibit typical characteristics with a transition from the paramagnetic-insulator state to the ferromagnetic-metallic state at a temperature peak (T _p ) ranging from 258 to 270 K. However, the LCMO/MgO films exhibited a semiconducting behavior without any transition. Based on the R(T) measurement, we calculated the temperature coefficient of resistance (TCR) for a bolometric application and we obtained 22%/K, 10.2%/K and 27.5%/K for the film grown on the LSAT, STO and LAO substrates, respectively. This difference in the TCR properties is related to the strain induced by the lattice mismatch between LCMO and the different substrates.     

Quantum Bit-commitment for small storage based on quantum one-way permutations

We propose a quantum bit-commitment scheme based on quantum one-way permutations with the unconditionally binding and computationally concealing property. Our scheme reduces exponentially the number of bits which the receiver needs to store until, the opening phase compared with the classical counterpart. Keisuke Tanaka, Ph.D.: He is Assistant Professor of Department of Mathematical and Computing Sciences at Tokyo Institute of Technology. He received his B.S. from Yamanashi University in 1992 and his M.S. and Ph.D. from Japan Advanced Institute of Science and Technology in 1994 and 1997, respectively. For each degree, he majored in computer science. Before joining Tokyo Institute of Technology, he was Research Engineer at NTT Information Sharing Platform Laboratories. His research interests are cryptography, quantum computation, circuit complexity, and the design and analysis of algorithms.     

Quantum Monte Carlo Device Simulation of Nano-Scaled SOI-MOSFETs

Quantum transport properties of nano-scaled SOI-MOSFETs are investigated based on a quantum Monte Carlo (MC) device simulation. The quantum mechanical effects are incorporated in terms of a quantum correction of potential in the well-developed particle MC computational techniques. The ellipsoidal multi-valleys of silicon conduction band are also considered in the simulation. First, the validity of the quantum MC technique is verified by comparing the simulated results with a self-consistent Schrödinger-Poisson solution at thermal equilibrium. Then, we apply the technique to non-equilibrium and quasi-ballistic quantum transport in nano-scaled SOI-MOSFETs.     

Effect of Shear Rate Distribution on Particle Aggregation in a Stirred Vessel

The modeling of particle aggregation under a simple shear flow and the extension of the model to a stirred vessel is described. The model quantitatively demonstrates the change of the number of aggregates with time for each shear rate. This number increased with higher shear rate and, conversely, the aggregate size became small when raising the shear rate. This was because aggregates were broken by the stronger shear force. The number of aggregates for different impellers was determined. The shear rate was back‐calculated from the experimentally obtained aggregate size and the model equation. This shear rate was different from that estimated from the Metzner‐Otto method, consequently, some revisions of the Metzner‐Otto equation might be necessary for its application to particle aggregation.     

A Study of Mutual Coupling between Vertical Grounding Electrodes

This paper investigates the mutual grounding impedance between vertical grounding electrodes based on field measurements and FDTD simulations. In the case of vertical electrodes, the mutual impedance between the electrodes is almost completely independent of the electrode length, and thus the induced voltage is nearly constant as the electrode length becomes longer. This characteristic is different from that of an overhead conductor, where the electromagnetic‐induced voltage is proportional to the conductor length. The greater the separation distance between the electrodes, the smaller the induced voltage, as in the case of an overhead conductor. The propagation speed increases as the separation increases. It is found that the speed is not necessarily proportional to the inverse of the relative permittivity of the earth.