Anomaly of Thermal Properties in Thin Films of La1-xSrxCoO3 Series Synthesized with a Combinatorial Processing

2001 ◽  
Vol 700 ◽  
Author(s):  
Yoshiaki Takata ◽  
Yutaka Adachi ◽  
Hajime Haneda ◽  
Yoshiki Wada ◽  
Makoto Ohtani ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
High Precision ◽  
Distribution Profile ◽  
Excitation Light ◽  
X Ray ◽  
Fundamental Wavelength ◽  
Thermal Diffusivities ◽  
Grating Spacing

AbstractThe thermal diffusivities throughout a composition-spread film comprising La1- xSrxCoO3 series were determined by Transient Reflecting Grating (TRG) measurements. Thermal diffusivities of transparent SrCoO3 film and SrTiO3 substrate were determined by using third harmonics having wavelength of 266 nm as an excitation light with only a certain length of grating spacing. The thermal diffusivities of them were 0.02 and 0.05 cm2/s, respectively. With regard to untransparent thin films, the experiment was performed by setting three kinds of grating spacing for the excitation light having the fundamental wavelength, 800 nm in order to obtain high precision. The distribution profile of obtained values of the thermal diffusivity throughout the sample was traced as 0.06 - 0.18 - 0.01 cm2/s corresponding to the variation of in La1-xSrxCoO3, thus showing a convex profile, however, this anomalous profile was verified by comparing with the data obtained by the X-ray diffractometer.

PHOTOACOUSTIC STUDIES ON TiAlN NANOSTRUCTURED THIN FILMS

2007 ◽  
Vol 21 (22) ◽  
pp. 3889-3900 ◽  
Author(s):  
R. SRINIVASAN ◽  
A. ALBERT IRUDAYARAJ ◽  
P. KUPPUSAMI ◽  
E. MOHANDAS ◽  
S. KALAINATHAN ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Bulk Materials ◽  
Flow Rates ◽  
X Ray ◽  
Titanium Aluminium

Nanostructured titanium aluminium nitride ( TiAlN ) thin films were prepared on Si (111) substrate by reactive DC magnetron sputtering technique for various N 2 flow rates. X-ray diffraction showed that the films are nanocrystalline and the grain size decreases from 14 nm to 5 nm as the N 2 flow rate is increased. The thermal properties are then studied by photoacoustic (PA) spectroscopy. The study revealed an increase in thermal diffusivity and conductivity with increasing N 2 flow rates, and the measured values of the thermal properties are significantly lower than those obtained with bulk materials which constitute TiAlN .

Anomaly of Thermal Properties in Thin Films of La1-x SrxCoO3 Series Fabricated as Thermoelectric Materials

2002 ◽  
Vol 730 ◽  
Author(s):  
Yoshiaki Takata ◽  
Hajime Haneda ◽  
Yutaka Adachi ◽  
Yoshiki Wada ◽  
Takefumi Mitsuhashi ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Thermoelectric Materials ◽  
Signal Analysis ◽  
Material Synthesis ◽  
Thermo Electric ◽  
Optical Pump ◽  
Pump And Probe ◽  
Reflection Geometry

AbstractComposition spreads of La1-xSrxCoO3 (LSCO) were synthesized as thermo-electric transducer material by means of combinatorial material synthesis, and information on their thermal diffusivity throughout the specimens was obtained. Meanwhile, it is anticipated that the composition spreads of LSCO have a variety of characteristic properties of light absorption corresponding to their composition, namely their compositional variable, x. Hence, we used transient optical pump-and-probe techniques in a reflection geometry to measure thermal diffusion times on LSCO. The results of signal analysis indicate that LSCO is a peculiar synthesized substance whose apparent thermal diffusivity, 1/ι, changes abruptly at the critical point, where the compositional variable x is equal to 0.3.

Photothermal methods for determination of thermal properties of bulk materials and thin films

Open Physics ◽  
2010 ◽  
Vol 8 (2) ◽  
Author(s):  
Jerzy Bodzenta ◽  
Anna Kaźmierczak-Bałata ◽  
Jacek Mazur
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Heat Transport ◽  
Temperature Fields ◽  
Nonstationary Temperature ◽  
Measuring Techniques ◽  
Heat Transport Properties ◽  
Photothermal Methods

AbstractInformation on the thermal properties of materials is very important both in fundamental physical research and in engineering applications. The development of materials with desirable heat transport properties requires methods for their experimental determination. In this paper basic concepts of the measurement of parameters describing the heat transport in solids are discussed. Attention is paid to methods utilizing nonstationary temperature fields, especially to photothermal methods in which the temperature disturbance in the investigated sample is generated through light absorption. Exemplary photothermal measuring techniques, which can be realized using common experimental equipment, are described in detail. It is shown that using these techniques it is possible to determine the thermal diffusivity of bulk transparent samples, opaque and semi-transparent plate-form samples, and the thermal conductivity of thin films deposited on thick substrates. Results of the investigation of thermal diffusivity of the ground in the polar region, which is based on the analysis of the propagation of the thermal wave generated by sun-light, are also presented. Based on chosen examples one can state that photothermal techniques can be used for determination of the thermal properties of very different materials.

Microstructure and Thermal Features of a-Si:H and nc-Si:H Thin Films Produced by Rf Sputtering

2006 ◽  
Vol 514-516 ◽  
pp. 23-27
Author(s):  
V. Thaiyalnayaki ◽  
M.Fátima Cerqueira ◽  
Francisco Macedo ◽  
João Alves Ferreira
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Thermal Properties ◽  
Rf Sputtering ◽  
Nanocrystalline Silicon ◽  
Transport Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicon Thin Films ◽  
Thermal Features

Amorphous and nanocrystalline silicon thin films have been produced by reactive r.f. sputtering and their microstructure, optical and thermal properties were evaluated. A good correlation was found between the microstructure determined by Raman spectroscopy and X- ray diffraction and the thermal transport parameters.

Heat conduction in silicon thin films: Effect of microstructure

1995 ◽  
Vol 10 (8) ◽  
pp. 1889-1896 ◽  
Author(s):  
Lanhua Wei ◽  
Mark Vaudin ◽  
Cheol Song Hwang ◽  
Grady White ◽  
Jason Xu ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Chemical Vapor ◽  
Bulk Silicon ◽  
Amorphous Films ◽  
Silicon Thin Films ◽  
Diffusivity Measurements ◽  
Pressure Chemical ◽  
Wave Technique

A study was made of the thermal properties of low pressure chemical vapor deposition (LPCVD) silicon thin films with amorphous and polycrystalline microstructures, produced by varying the substrate temperature. Thermal diffusivity measurements were conducted using a thermal wave technique. The thermal diffusivity of the polycrystalline films was found to be about three times that of the amorphous films, but about one eighth that of bulk silicon single crystals. There was also an indication that the diffusivity increased with deposition temperature above the transition temperature from the amorphous to the polycrystalline state. The relationships between the thermal properties and microstructural features, such as grain size and grain boundary, are discussed.

High-precision spin coater for a synchrotron radiationin situGISAXS system: for the investigation of formation mechanisms of self-assembled structures in polymer thin films

2013 ◽  
Vol 46 (6) ◽  
pp. 1610-1615 ◽  
Author(s):  
Hiroki Ogawa ◽  
Tsukasa Miyazaki ◽  
Keisuke Shimokita ◽  
Akihiko Fujiwara ◽  
Mikihito Takenaka ◽  
...  
Keyword(s):  
Thin Films ◽  
High Precision ◽  
Film Formation ◽  
Polymer Thin Films ◽  
Film Surface ◽  
Maximum Speed ◽  
Formation Mechanisms ◽  
X Ray ◽  
Self Assembled ◽  
Spin Coater

A high-precision spin-coater system has been developed for the investigation of formation mechanisms of self-assembled structures in polymer thin films. The spin coater was designed to have small axial deflection (<2.6 µm at the maximum speed of 2000 r min−1) during rotation in order to maintain the relative position with respect to the incident X-ray beam, and to be compact (70 mm) in height to facilitate incorporation into anin situsynchrotron radiation grazing-incidence small-angle X-ray scattering (GISAXS) system. The first results of simultaneous measurements on the morphology and film thickness of a triblock copolymer with time resolution of 64 ms during thin-film formation at 2000 r min−1provide indispensable information for understanding the vertically grown lamellar structure on the film surface.

Synthesis of Electrospun Titania Nanofibers for Thermal Lens Study in Heat Transport Applications

2018 ◽  
Vol 936 ◽  
pp. 58-62
Author(s):  
José Alfredo Pescador-Rojas ◽  
José Luis Jiménez-Pérez ◽  
José Francisco Sánchez-Ramírez ◽  
Rubén Gutiérrez-Fuentes ◽  
Zormy Nacary Correa-Pacheco ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Lens ◽  
Fiber Diameter ◽  
Sol Gel ◽  
Average Diameter ◽  
Thermal Lens Spectrometry ◽  
X Ray ◽  
Complementary Techniques ◽  
Thermal Diffusivities ◽  
Titania Nanofibers

Thermal lens spectrometry (TLS) technique was used to obtain the thermal diffusivity of electrospun Titania nanofibers (TiO2), with average diameter size of 50-80 nm, in water. TiO2nanofibers have been successfully prepared by sol-gel and electrospining techniques. TLS provides reliable alternative to measure the thermal diffusivities of semitransparent materials and low thermal diffusivities. The results show that the nanofluid thermal diffusivity increases with the presence of nanofibers. Complementary techniques: scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS) were employed to characterize the nanofibers morphology, average fiber diameter and chemical composition, respectively.

A Novel Method to Determine The Mechanical Properties of Ultra-Thin Films.

1998 ◽  
Vol 511 ◽  
Author(s):  
C. C. White ◽  
W. L. Wu
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Physical Properties ◽  
High Precision ◽  
Quartz Crystal Microbalance ◽  
Polymer Films ◽  
Quartz Crystal ◽  
X Ray ◽  
Novel Method ◽  
Established Technique

ABSTRACTRecent experimental results based on x-ray reflectivity[1, 2], and ellipsometry[3] have demonstrated that physical properties of polymer films thinner than one micron may deviate significantly from bulk values[4]. The mechanical properties of the ultra-thin films (sub-micron) are experimentally difficult to determine with precision. The quartz crystal microbalance is an established technique for measuring properties of polymer thin films of a few microns thick. [5–7] Recently this quartz crystal microbalance technique has been modified for measuring the mechanical properties of sub-micron polymer films with high precision. The details and preliminary results from this recently modified quartz crystal microbalance technique will be presented.

Thermal diffusivity of (Ca1–xSrx)3Co4O9 thin films using transient grating configuration

2003 ◽  
Vol 18 (10) ◽  
pp. 2473-2477 ◽  
Author(s):  
Yoshiaki Takata ◽  
Yutaka Adachi ◽  
Hajime Haneda ◽  
Yoshiki Wada ◽  
Takefumi Mitsuhashi ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Diffusivity ◽  
Light Pulse ◽  
Measurement Technique ◽  
Room Temperature ◽  
Optical Diffraction ◽  
Transient Grating ◽  
The Past ◽  
Thermal Diffusivities

The past impossibility to create optical diffraction fringe image out of transparent TiO2(100) substrate was overcome by pumping light pulse of 266-nm wavelength. Thermal diffusivities (D) of TiO2(100) substrate and (Ca1–xSrx)3Co4O9 (0 ≤ x ≤ 0.125) thin films can successfully be determined with a newly proposed transient grating configuration method arising from a generic nanoscale measurement technique. The D values obtained at room temperature were 0.04 cm2/s for the former and 0.07–0.12 cm2/s for the latter, respectively.

Pulse-to-Pulse Laser Stability Effects on Multiple Shot Excimer Laser Crystallized a-Si Thin Films

1994 ◽  
Vol 343 ◽  
Author(s):  
R. I. Johnson ◽  
G. B. Anderson ◽  
J. B. Boyce ◽  
D. K. Fork ◽  
P. Mei ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Energy Density ◽  
Pulse Laser ◽  
Laser Fluence ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Distribution Profile ◽  
X Ray ◽  
Silicon Thin Films

ABSTRACTLaser crystallized amorphous silicon thin films on quartz exhibit a peak in the grain size, electron mobility and the Si (111) x-ray intensity as a function of the laser fluence, substrate temperature, film thickness, and the number of laser shots per unit area. The peak in grain size has also been shown to be dependent: on the stability of the pulse-to-pulse laser energy density, particularly at high shot densities. The shape of the distribution profile of the pulse-to-pulse laser fluence can significantly alter the grain growth at higher shot densities. The modified growth can be expressed by a simple model based on the mean and standard deviation of the laser energy density relative to the characteristic fluence at which the grain size, mobility, and Si (111) x-ray intensities are maximized.

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