S. Chaudhuri

Bio: S. Chaudhuri is an academic researcher. The author has contributed to research in topics: Magnetoresistance & Hall effect. The author has an hindex of 1, co-authored 1 publications receiving 40 citations.

In situ measurement of Hall effect, magnetoresistance, resistivity, and TCR of bismuth films

Abstract: In situ measurements of Hall effect, magnetoresistance, resistivity, and temperature coefficient of resistivity of bismuth films (700–2600 A) were carried out in a specially designed evacuation chamber. The films were deposited on a glass substrate at 150°C and at a pressure of ∼10−6 Torr. The values of the mean free path and specular scattering parameter obtained were 14100 A and 0.5, respectively. The effect of the grain boundary on the electrical resistivity was also accounted for in the light of the Mayadas‐Shatzkes theory.

The effect of grain boundary scattering on the electron transport of aluminium films

Abstract: The electrical resistivity and temperature coefficient of the resistivity of polycrystalline aluminium films (500-1700 AA) deposited on to a glass substrate were measured in situ at temperatures of 50, 100 and 140 degrees C. The effect of grain boundary scattering was analysed using the Mayadas-Shatzkes theory (1970). It is observed that the Mayadas-Shatzkes equation reproduces the experimental observation quite faithfully with R=0.28 and p=0, which indicates that the contribution from grain boundary scattering should be quite appreciable.

In situ four-point conductivity and Hall effect apparatus for vacuum and controlled atmosphere measurements of thin film materials

Abstract: An ultrahigh vacuum (UHV) chamber equipped with a fixture for in situ four-point Van Der Pauw conductivity and Hall effect measurements has been constructed and attached to a multichamber thin film synthesis and characterization system. The combined systems allow for film synthesis and characterization of microstructure, chemical composition, morphology, and electronic transport properties without air exposure. The four-point measurement fixture features spring-loaded probes for electrical contacts and temperature measurement and a sample docking mechanism designed to minimize probe damage to the films. The electronics were designed for measurement of high resistance samples. Measurements can be made at sample temperatures from 25 to 450 °C in selected gas environments from UHV to atmospheric pressure. The design and performance of the system are reported, and representative results on the electronic transport properties of n-type Si (100) and tungsten oxide films on sapphire are presented.

Temperature and thickness dependence of electrical and thermal transport coefficients of Bi1–xSbx films in an anisotropic, non-degenerate two-band model

Abstract: The thickness and temperature dependences of electrical and thermal transport coefficients (e.g. electrical conductivity, thermoelectric power, thermal conductivity) of Bi1–xSbx films are described by a non-degenerated two-band model, considering the anisotropic elliptical band structure (many-valley model) of bulk Bi1–xSbx. The transport coefficients are measured in the temperature range 80 to 400 K on films with thicknesses 20 to 400 nm and the results are interpreted and discussed using the deduced relations. Die Schichtdicken- und Temperatura bhangigkeit elektrischer und thermischer Transportkoeffi-zienten (z. B. der elektrischen Leitfahigkeit, der Thermokraft, der Warmeleitfahigkeit) von Bi1–xSbx-Schichten wird im Rahmen eines nicht entarteten Zweiband-Modells unter Berucksichtigung der anisotropen elliptischen Bandstruktur (many valley model) von massivem Bi1–xSbx beschrieben. Die Transportkoeff izienten werden im Temperaturbereich 80 bis 400 K an Schichten von 20 bis 400 nm Dicke gemessen, und die Ergebnisse werden mit den abgeleiteten Beziehungen interpretiert und diskutiert.

Size-dependent structural characteristics of thin bismuth films

Abstract: Bismuth thin films in the thickness range from 10 to 200 nm were deposited on glass substrates by thermal evaporation. The films were investigated by electron microscopy and X-ray diffraction. No anomalous dependence of the structural features on the film thickness was observed but only a normal monotonic variation. All the samples were polycrystalline with a high degree of preferred orientation. The [0001] H or [111] R fibre texture was against heat treatment. The residual strain decreased abruptly with increasing thickness up to 30 nm while the grain size increased up to a thickness of 100 nm and then exhibits almost no further change. The substructure within the individual grain, such as twining and/or stacking faults, was considered on the basis of the large values of grain size revealed by direct observation with transmission electron microscopy compared with those obtained from X-ray diffraction line profile analysis. A structure-properties (electrical) intercorrelation was proved.

Hall coefficient of thin films in a mean free path model

Abstract: Defining an effective relaxation time and then using the Boltzmann transport equation, analytical expressions have been derived, in the case of nearly specular scattering on external surfaces (p>or=0.5), for the Hall coefficient and conductivity in thin metallic films subjected to a transverse magnetic field. The results for moderately high magnetic field agree well with previous theoretical works; at low magnetic field the Hall coefficient in thin films is greater than the bulk value RH0 and becomes identical with RH0 in strong magnetic field. The theoretical predictions agree well with experimental data on copper and potassium thin films.