2,462 research outputs found
Magnetic-Field-Induced Mott Transition in a Quasi-Two-Dimensional Organic Conductor
We investigated the effect of magnetic field on the highly correlated metal
near the Mott transition in the quasi-two-dimensional layered organic
conductor, -(BEDT-TTF)Cu[N(CN)]Cl, by the resistance
measurements under control of temperature, pressure, and magnetic field. It was
demonstrated that the marginal metallic phase near the Mott transition is
susceptible to the field-induced localization transition of the first order, as
was predicted theoretically. The thermodynamic consideration of the present
results gives a conceptual pressure-field phase diagram of the Mott transition
at low temperatures.Comment: 4 pages, 4 figure
Field-induced staggered magnetic moment in the quasi-two-dimensional organic Mott insulator -(BEDT-TTF)Cu[N(CN)]Cl
We investigated the magnetism under a magnetic field in the
quasi-two-dimensional organic Mott insulator
-(BEDT-TTF)Cu[N(CN)]Cl through magnetization and
C-NMR measurements. We found that in the nominally paramagnetic phase
(i.e., above N\'eel temperature) the field-induced local moments have a
staggered component perpendicular to the applied field. As a result, the
antiferromagnetic transition well defined at a zero field becomes crossover
under a finite field. This unconventional behavior is qualitatively reproduced
by the molecular-field calculation for Hamiltonian including the exchange,
Dzyaloshinsky-Moriya (DM), and Zeeman interactions. This calculation also
explains other unconventional magnetic features in
-(BEDT-TTF)Cu[N(CN)]Cl reported in the literature. The
present results highlight the importance of the DM interaction in field-induced
magnetism in a nominally paramagnetic phase, especially in low-dimensional spin
systems.Comment: 11 pages, 12 figures, selected for Editors' Suggestion
A Compact Tea Co2 Laser for Field-based Spectrochemical Analysis of Geological Samples
A compact capacitor-transfer TEA CO2 laser of 180 mJ output energi and 50 ns pulse duration in half width has been designed and constructed for field use. This laser is suitable for laser microprobe spectrochemical analysis on geological and mining samples. Experiments show that the use of helium as a surrouding gas suppresses the continous emission spectrum of the plasma, thus increasing the S/N ratio. Using glass as standard samples, the minimum detectable concentrations are estimated with Zn neutral line and F ionic line to be 60 ppm and 500 ppm, respectively.
Keywords : lasers ( Compact TEA CO2 ), field-based analysis, laser microprobe analysi
A COMPACT TEA CO2 LASER FOR FIELD-BASED SPECTROCHEMICAL ANALYSIS OF GEOLOGICAL SAMPLES
A compact capacitor-transfer TEA CO2 laser of 180 mJ output energi and 50 ns pulse duration in half width has been designed and constructed for field use. This laser is suitable for laser microprobe spectrochemical analysis on geological and mining samples. Experiments show that the use of helium as a surrouding gas suppresses the continous emission spectrum of the plasma, thus increasing the S/N ratio. Using glass as standard samples, the minimum detectable concentrations are estimated with Zn neutral line and F ionic line to be 60 ppm and 500 ppm, respectively.
Keywords : lasers ( Compact TEA CO2 ), field-based analysis, laser microprobe analysi
Analysis of dynamic characteristics of fluid force induced by labyrinth seal
Flow patterns of the labyrinth seal are experimentally investigated for making a mathematical model of labyrinth seal and to obtain the flow induced force of the seal. First, the flow patterns in the labyrinth chamber are studied on the circumferential flow using bubble and on the cross section of the seal chamber using aluminum powder as tracers. And next, the fluid force and its phase angle are obtained from the measured pressure distribution in the chamber and the fluid force coefficients are derived from the fluid force and the phase angle. Those are similar to the expression of oil film coefficients. As a result, it is found that the vortices exist in the labyrinth chambers and its center moves up and down periodically. The pressure drop is biggest in the first stage of chambers and next in the last stage of chambers
Possibility of Macroscopic resonant Tunneling near the Superconductor- Insulator Transition in YBaCuO Thin Films
Experimental results of I-V characteristics near the superconductor-insulator
transition observed for disorder-tuned YBaCuO thinfilms are presented. The I-V
characteristics exibit new quasiperiodic structures as a function of the
current. The current interval, the number of the dI/dV peaks, and the magnetic
field dependence of the peaks are consistent with the theoretical predictions
of the resonant tunneling of a phase particle ina tilted-cosine potential for
asingle Josephson junction with small capacitance.Comment: 7 pages, 4 figures, in press (Europhys. Lett.
- …