RSI Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

Dec 2005

Volume 76, Issue 12, Articles (12xxxx)

Return to All Sections
back to top
RSS Feeds

Eucentric four-axis ultrahigh vacuum goniometer for reflection high-energy electron diffraction applications

A. Schmehl, R. R. Schulz, and J. Mannhart

Rev. Sci. Instrum. 76, 123901 (2005); http://dx.doi.org/10.1063/1.2138687 (4 pages)

Online Publication Date: 14 December 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The design and performance of a four-axis low-profile eucentric UHV goniometer for in situ reflection high-energy electron diffraction (RHEED) studies during film deposition is reported. The design provides one translational and three rotational degrees of freedom that are fully independent. Although developed to facilitate high-pressure RHEED during the growth of oxide thin films by pulsed laser deposition, this goniometer design is applicable to other UHV techniques including molecular beam epitaxy. The goniometer requires only a single DN 100 CF flange (6 in. o.d., 100 mm i.d.), making it suitable for small deposition systems, too. Samples, attached to a resistively heated holder, can be easily transferred on and off of the goniometer without breaking vacuum. The holder accommodates samples up to 10 mm×10 mm in size and allows them to be heated to 900 °C in pure oxygen while being attached to the goniometer. Full eucentric motion of the hot sample is possible with a typical axis precision of <0.1°. Most of the mechanism is located in air, allowing the use of standard materials and lubricants, substantially reducing the in-vacuum mechanics, and increasing the precision, reliability, and robustness of the system.
Show PACS
07.85.-m X- and γ-ray instruments
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
81.15.Fg Pulsed laser ablation deposition
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Composite bimetallic gasket and compact mechanical anvil retainer for magnetic measurements in a diamond-anvil cell to 30 GPa

Mamoru Ishizuka

Rev. Sci. Instrum. 76, 123902 (2005); http://dx.doi.org/10.1063/1.2140447 (4 pages) | Cited 2 times

Online Publication Date: 14 December 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A composite gasket was designed for diamond-anvil cells where the load was supported mainly by the inner part made of NiCrAl with a diameter slightly larger than the culet of the anvil. A BeCu girdle encased the NiCrAl washer and prevented it from fracturing. The thickness of the gasket was about 30 μm at a pressure of 30 GPa applied with a pair of diamond anvils having 500 and 550 μm culets. The magnetic contribution of the composite gasket to the background signal was almost the same as that of a BeCu gasket having the same size. The diamond anvils were fixed to the pistons with four miniature screws through small BeCu rings that were press fitted to the circumference of the diamond anvils. The performance of this composite gasket together with the anvil retainer was illustrated by the measurements of the temperature dependence of the dc magnetic susceptibility of Cs2CuF4 under various pressures up to 26 GPa using a superconducting quantum interference device vibrating coil magnetometer.
Show PACS
07.55.-w Magnetic instruments and components
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
75.30.Cr Saturation moments and magnetic susceptibilities

Small-volume, ultrahigh-vacuum-compatible high-pressure reaction cell for combined kinetic and in situ IR spectroscopic measurements on planar model catalysts

Z. Zhao, T. Diemant, T. Häring, H. Rauscher, and R. J. Behm

Rev. Sci. Instrum. 76, 123903 (2005); http://dx.doi.org/10.1063/1.2140449 (8 pages) | Cited 3 times

Online Publication Date: 14 December 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We describe the design and performance of a high-pressure reaction cell for simultaneous kinetic and in situ infrared reflection (IR) spectroscopic measurements on model catalysts at elevated pressures, between 10−3 and 103 mbars, which can be operated both as batch reactor and as flow reactor with defined gas flow. The cell is attached to an ultrahigh-vacuum (UHV) system, which is used for sample preparation and also contains facilities for sample characterization. Specific for this design is the combination of a small cell volume, which allows kinetic measurements with high sensitivity under batch or continuous flow conditions, the complete isolation of the cell from the UHV part during UHV measurements, continuous temperature control during both UHV and high-pressure operation, and rapid transfer between UHV and high-pressure stage. Gas dosing is performed by a designed gas-handling system, which allows operation as flow reactor with calibrated gas flows at adjustable pressures. To study the kinetics of reactions on the model catalysts, a quadrupole mass spectrometer is connected to the high-pressure cell. IR measurements are possible in situ by polarization-modulation infrared reflection-absorption spectroscopy, which also allows measurements at elevated pressures. The performance of the setup is demonstrated by test measurements on the kinetics for CO oxidation and the CO adsorption on a Au/TiO2/Ru(0001) model catalyst film at 1–50 mbar total pressure.
Show PACS
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials
07.75.+h Mass spectrometers
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques

Production and characterization of micron-sized filaments of solid argon

Michael Grams, Boleslaw Stasicki, and J. Peter Toennies

Rev. Sci. Instrum. 76, 123904 (2005); http://dx.doi.org/10.1063/1.2135277 (9 pages) | Cited 1 time

Online Publication Date: 21 December 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A continuous 50-μm-diam filament of solid argon is produced in a moderate vacuum (4.2×10−3 mbar) by cooling argon gas to 70–90 K over the last 8 mm of a long fused silica capillary. Prior to formation of the straight filament the jet shows different stages characterized by spraying, snowballing, or spiraling filaments as documented by charge-coupled device (CCD) camera microscope pictures. Consecutive CCD pictures are used to measure the filament velocities, which increase with the driving gas pressure P0 up to about 4.0 cm/s at P0 = 400 bars with an intermediate peak at about 80 bars. This technique may find applications for producing wall-less cryogenic matrices, targets for laser plasma sources of extreme UV and soft-x-ray sources, plasma implosion experiments, or H2 pellets for injection into fusion reactors.
Show PACS
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment
47.27.wg Turbulent jets

X-ray-absorption fine structure measurement with parallel-plate capacitor: Observation of surface electronic states of metals

Masashi Ishii and Aiko Nakao

Rev. Sci. Instrum. 76, 123905 (2005); http://dx.doi.org/10.1063/1.2148998 (7 pages) | Cited 1 time

Online Publication Date: 27 December 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
For surface electronic state analyses of metals, we developed a new x-ray-absorption fine structure (XAFS) measurement technique with a parallel-plate capacitor. Since the capacitance is changed by x-ray-induced photoionization on the metal surface, the surface XAFS spectrum of a metal can be obtained from the capacitance dependent on the x-ray photon energy. We adopted this technique to the Cu metals. The XAFS spectrum at the Cu K absorption edge is different from the conventional XAFS spectrum of either Cu or Cu2O. This finding suggests that the XAFS spectrum indicates two-dimensional (2D) electronic states between the Cu bulk and the Cu2O native oxide layer. The 2D electronic states were characterized by degeneration of Cu 4pπ and a blueshift of Cu 4pσ. These characteristics can be explained by hybridization of vertical Cu 4pz with horizontal 4px and 4py in CuO-like structure at the interface.
Show PACS
07.85.Nc X-ray and γ-ray spectrometers
78.70.Dm X-ray absorption spectra
73.20.At Surface states, band structure, electron density of states

A double-beam common path laser interferometer for the measurement of electric field-induced strains of piezoelectric thin films

Z. Huang and R. W. Whatmore

Rev. Sci. Instrum. 76, 123906 (2005); http://dx.doi.org/10.1063/1.2149002 (4 pages) | Cited 1 time

Online Publication Date: 27 December 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report in this paper the development of a modified Mach-Zehnder-type double-beam common path laser interferometer for the measurement of electric field-induced strain in piezoelectric materials, especially for the thin films. Compared to previous interferometers, this one is simpler and more compact, and the measurement and reference arms share a common path for most of the optical length. Example results have been reported for the quartz, lead zirconate titanate (PZT) ceramic sample, and PZT thin films. Double- and single-beam measurements have been carried out at different frequencies for the same spot of a PZT thin-film sample and it was found that the single-beam values were a few times of the values as obtained from the double-beam technique. This phenomenon is confirmed by the laser scanning vibrometer measurements.
Show PACS
07.60.Ly Interferometers
07.10.Pz Instruments for strain, force, and torque
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.65.Ly Strain-induced piezoelectric fields

Optical absorption spectrum measurement of films at a low temperature using photothermal bending spectroscopy

Hitoe Habuchi and Daisuke Harada

Rev. Sci. Instrum. 76, 123907 (2005); http://dx.doi.org/10.1063/1.2149148 (4 pages)

Online Publication Date: 27 December 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical absorption spectrum of a semiconductor film was obtained at a low temperature using an optical cantilever method called photothermal bending spectroscopy. The film, clamped on one side in a cryostat, was uniformly cooled with nitrogen gas. The product of the measurable optical absorption coefficient and the thickness of the film was better than 1×10−3 at 110 K. We demonstrated that the 1.74 eV peak in the optical absorption spectrum of a C60 film could not be observed at room temperature, but could be observed at 110 K due to a sharpening of the Urbach tail slope.
Show PACS
78.66.Tr Fullerenes and related materials
78.40.Ri Fullerenes and related materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close