Nobuo Miyamoto

Remarkably low value of work function on W(100) produced by Y–O composite layer

Electrical dipoles on a metal surface is believed to reduce the work function of the metal remarkably. Here, it is shown that slight yttrium layer with oxygen remarkably reduce the work function on W(100) surface. The reduced amount is much larger than Zr-O dipole on W(100). We believe YO/W(100) surface has a potential ability much better than the ZrO/W(100), which is widely adopted for scanning electron microscopes as bright cathodes.

Fundamental characteristics of the QFP measured by the DC SQUID

The fundamental characteristics are described of the quantum flux parametron (QPF), measured by a method in which the output signals of the QFP are detected with a DC SQUID. The DC SQUID linearly and continuously converts the output current of the QFP to voltage, allowing the output signal of the QFP to be measured as the voltage of the DC SQUID. The fundamental characteristics of the QFP have been experimentally confirmed in detail. >

Transmission electron microscope observation of a NbN/Nb oxide/NbN trilayer structure

A NbN/Nb oxide/NbN trilayer film was fabricated and its cross‐sectional structure was observed by a transmission electron microscope. The NbN oxide thickness was taken to be as thin as that (∼4 nm) of a typical Josephson junction in order to clarify the tunnel barrier structure. It was proven that the Nb oxide layer was not uniform and this nonuniformity was correlated with the crystal structure, grain boundary, and crystal orientation of the lower NbN film. A variety of oxide thicknesses may be responsible for the local distribution of tunneling currents within the Josephson junction.

Emission stability of a field emitter array observed by an emission microscope

Emission stability is the most stringent requirement for a field emitter array (FEA) in practical applications. When fluctuating events occur stochastically, the fluctuation in electron emission reduces with 1/N, where N is the number of individual cathodes. So, the total current of the FEA is expected to be stable. However, the fluctuation does not necessarily occur stochastically, and the mode of fluctuation of each individual microtip is different from tip to tip. We observed the fluctuation of each microtip by use of an emission microscope. The behaviors are classified due to the emission mode. As a result of observation, the modes of fluctuation can be classified in two types. One has a dependence IP product, which is the product of the total current and pressure, and the other has not. To explain the former fluctuation, we propose a model where ion bombardment is due to desorbed gas molecules from the gate hole side of the emitting microtip. The model successfully explains the measured results. Howe...

Remarkably low value of work function on W(100) produced by Y-O composite layer

Electrical dipoles on a metal surface is believed to reduce the work function of the metal remarkably. Here, it is shown that slight yttrium layer with oxygen remarkably reduce the work function on W(100) surface. The reduced amount is much larger than Zr-O dipole on W(100). We believe YO/W(100) surface has a potential ability much better than the ZrO/W(100), which is widely adopted for scanning electron microscopes as bright cathodes.

Improving the Gain of the Quantum Flux Parametron

The gain of parametron-type devices like the Quantum Flux Parameffon (QFP) is affected by non-uniformity which causes an apparent input bias. A method to improve gain by circuit design is considered. A booster, a pre-activated QFP attached to the ouqlut of a clock-activated QFP, improves gain by doubling total output crurent without significantly increasing minimum input crurenl The boosters operation is analyzed theoretically and compared to results obtained from experiments on fabricated test circuits.

Experimental and Simulation Study of an Auxiliary Circuit to Improve Gain of the Quantum Flux Parametron

The gain of parametron-type devices like the Quantum Flux Parametron (QFP) is reduced by non-uniformity which causes an apparent input bias. A method to improve gain by circuit design is considered. A booster, a dc-activated QFP attached to the output of a clock-activated QFP, improves gain by doubling total output current without significantly increasing minimum input current. The boosters operation is analyzed theoretically from its quasi-static behavior and compared to results obtained from low-speed experiments on fabricated test circuits and computer simulations at high-clock rates.