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Electromigration and soret effect in cobalt
Vol. 4, No. 3
ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOLIDS
the cathode side of the silver samples. The size of the voids ran up to 30 microns in dlameter and was observed to depend on the temperature, the amount of transport, and the protective atmosphere used. When the atmosphere was changed from argon gas to a 5 percent hydrogen 95 percent argon gas mixture, the rate of void formation was about two times faster although the void size was generally smaller. -
(Received 22 December 1965) 31. ELECTROMIGRATION AND S~ETEFFECT IN COBALT, Paul S. Ho (Department of Physics, Rensselaer Polytechnic Institute, Troy, New York). Present investigation aims to examine whether the electron-ion interaction in hole conductors follows the flow of charge carriers in electromigration experiments, as predicted by theory and observed in several electron conductors. Mass transport of cobalt, a hole conductor, 4amps/cm2 has been by a of marker under the influence of a measured direct current about l0 motion technique at temperatures from 1250 to 1360CC. The cobalt ions migrated to the cathode with a marker motion of about 2 i.i /day at 1360CC and an average effective charge of +1. 6e. This result would therefore indicate an affirmative answer if the valence charge is taken to be+0. 6e. A Soret effect, due to the presence of thermal gradient in the electromigration experiment, has also been observed; the ions migrated down the temperature gradient. The marker motion was about 7i.i/day at 1320°Cand 500CC/cm. The value of sj, the Soret coefficient, was found to increase from about 0.04°K~at 1200°Ctoabout 0. 12°Ir1 at 1360°C. The simple kinetic model, predicting a much lower value for sj, cannot adequately explain the experimental results. (Received 22 December 1965) 32. CONDUCTIVITY ANISOTROPY OF HOT
ELECTRONS IN n-TYPE SILICON BEATED BY MICROWAVE FIELDS. Chihiro Hamaguchi and Yoshio Inuishi (Faculty of Engineering, OsakaOsaka, University, Higashinoda, Mtyakojima-ku, Japan). The conductivity anisotropy of a n-type silicon in the range of the warm and hot electrons was measured by the average conductivity with the application of 9. 375-kMc microwave electron
~vit
heating pulse fields at room temperature. The Instantaneous conductivity under microwave application was found to agree, within expertmental error, with the dc conductivity measured at high dc fields on the sanie samples. The repopulation of the 400> valley for the <001> and <100> field directions were calculated as a function of the electric fields up to 7 ICV/crn, and found to be about 10% and 2.5% at 5kV/cm respectively. The anisotropy of the “warm electron coefficient ~“ was in good agreement with Schmidt-Tiedem~nn’stheory and the ratio v0 / B~ is about 0.47 at room temperature. The thermoelectric voltage” of the hot electrons due to a gradient in the electric field was measured at room temperature. The behavior was very sunilar to that of germanium obtained by Conwell and Zucker, and the proportionality of the thermoelectric voltage to the square of the peak microwave fields holds up to about 1000V/cm. (Received 14 January 1966). 33. PARTIAL PRESSURES OF Te~(g)IN FROM OPTICAL DENSth DA~A. EQUILIBRIUM WITH Gel... 6Tel + 6(c) R. F. Brebrick (Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02173). The partial pressures of Tea) in equilibrium with Ge-Te samples containing 1. 00, 49. 84, 49. 92, 50. 00, 50. 08, 50.30, 50.60,50. 70, 50. 85, 51. 01, 51.5, and 52.0 at. % Te have been determined between about 500 and 780°C bymeasuring the opiical density of the vapor at 4357 and 5000 1. The duta show that the m~rhnum melting point of Ge~~Te~+ (c) occurs at 724 ± ICC and 49.84 at.%Te. T~ieTe-rich solidus increases in Te-content with decreasing temperature to 500°Cwhere it is 51.32 at. % Te. The stoichiometric solid is in equilibrium with a 52. 0 at. % Te liquid and lies within the homageneity range down to at least 600°C. At 636°Cthe Gibbs free energy of formation of Ge~+ 7t I 6Tej. atm2, + ~ increases (c) from ideal monc*onically Te~)and with Ge(g)at.each % Tea at the rate of about 1.1 ± 0.03 kcal/mole/at. % Te. The partial molal enthalpies and entropies of Te and Ge in Gel 6Tej. + 6that the haveprimarily also beenTe-rich obtained. 2concluded It can be homogeneity range of Gei 6Te~~ 6(c) cannot be attributed to the propertI~esof tihs phase alone, which in fact tend to shift the homogeneity range toward Ge-rich compositions. -
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ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOLIDS
the cathode side of the silver samples. The size of the voids ran up to 30 microns in dlameter and was observed to depend on the temperature, the amount of transport, and the protective atmosphere used. When the atmosphere was changed from argon gas to a 5 percent hydrogen 95 percent argon gas mixture, the rate of void formation was about two times faster although the void size was generally smaller. -
(Received 22 December 1965) 31. ELECTROMIGRATION AND S~ETEFFECT IN COBALT, Paul S. Ho (Department of Physics, Rensselaer Polytechnic Institute, Troy, New York). Present investigation aims to examine whether the electron-ion interaction in hole conductors follows the flow of charge carriers in electromigration experiments, as predicted by theory and observed in several electron conductors. Mass transport of cobalt, a hole conductor, 4amps/cm2 has been by a of marker under the influence of a measured direct current about l0 motion technique at temperatures from 1250 to 1360CC. The cobalt ions migrated to the cathode with a marker motion of about 2 i.i /day at 1360CC and an average effective charge of +1. 6e. This result would therefore indicate an affirmative answer if the valence charge is taken to be+0. 6e. A Soret effect, due to the presence of thermal gradient in the electromigration experiment, has also been observed; the ions migrated down the temperature gradient. The marker motion was about 7i.i/day at 1320°Cand 500CC/cm. The value of sj, the Soret coefficient, was found to increase from about 0.04°K~at 1200°Ctoabout 0. 12°Ir1 at 1360°C. The simple kinetic model, predicting a much lower value for sj, cannot adequately explain the experimental results. (Received 22 December 1965) 32. CONDUCTIVITY ANISOTROPY OF HOT
ELECTRONS IN n-TYPE SILICON BEATED BY MICROWAVE FIELDS. Chihiro Hamaguchi and Yoshio Inuishi (Faculty of Engineering, OsakaOsaka, University, Higashinoda, Mtyakojima-ku, Japan). The conductivity anisotropy of a n-type silicon in the range of the warm and hot electrons was measured by the average conductivity with the application of 9. 375-kMc microwave electron
~vit
heating pulse fields at room temperature. The Instantaneous conductivity under microwave application was found to agree, within expertmental error, with the dc conductivity measured at high dc fields on the sanie samples. The repopulation of the 400> valley for the <001> and <100> field directions were calculated as a function of the electric fields up to 7 ICV/crn, and found to be about 10% and 2.5% at 5kV/cm respectively. The anisotropy of the “warm electron coefficient ~“ was in good agreement with Schmidt-Tiedem~nn’stheory and the ratio v0 / B~ is about 0.47 at room temperature. The thermoelectric voltage” of the hot electrons due to a gradient in the electric field was measured at room temperature. The behavior was very sunilar to that of germanium obtained by Conwell and Zucker, and the proportionality of the thermoelectric voltage to the square of the peak microwave fields holds up to about 1000V/cm. (Received 14 January 1966). 33. PARTIAL PRESSURES OF Te~(g)IN FROM OPTICAL DENSth DA~A. EQUILIBRIUM WITH Gel... 6Tel + 6(c) R. F. Brebrick (Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02173). The partial pressures of Tea) in equilibrium with Ge-Te samples containing 1. 00, 49. 84, 49. 92, 50. 00, 50. 08, 50.30, 50.60,50. 70, 50. 85, 51. 01, 51.5, and 52.0 at. % Te have been determined between about 500 and 780°C bymeasuring the opiical density of the vapor at 4357 and 5000 1. The duta show that the m~rhnum melting point of Ge~~Te~+ (c) occurs at 724 ± ICC and 49.84 at.%Te. T~ieTe-rich solidus increases in Te-content with decreasing temperature to 500°Cwhere it is 51.32 at. % Te. The stoichiometric solid is in equilibrium with a 52. 0 at. % Te liquid and lies within the homageneity range down to at least 600°C. At 636°Cthe Gibbs free energy of formation of Ge~+ 7t I 6Tej. atm2, + ~ increases (c) from ideal monc*onically Te~)and with Ge(g)at.each % Tea at the rate of about 1.1 ± 0.03 kcal/mole/at. % Te. The partial molal enthalpies and entropies of Te and Ge in Gel 6Tej. + 6that the haveprimarily also beenTe-rich obtained. 2concluded It can be homogeneity range of Gei 6Te~~ 6(c) cannot be attributed to the propertI~esof tihs phase alone, which in fact tend to shift the homogeneity range toward Ge-rich compositions. -
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