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Physical Sciences and Mathematics Commons

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Selected Works

San Jose State University

1975

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Properties Of Hxtas2, D. W. Murphy, F. J. Disalvo, G. W. Hull, J. V. Waszczak, S. F. Meyers, G. R. Stewart, S. Early, Juana Vivó Acrivos, T. H. Geballe Jan 1975

Properties Of Hxtas2, D. W. Murphy, F. J. Disalvo, G. W. Hull, J. V. Waszczak, S. F. Meyers, G. R. Stewart, S. Early, Juana Vivó Acrivos, T. H. Geballe

Juana Vivó Acrivos

The preparation of Hx TaS2 (0 < x < 0.87) is described. The compounds are only marginally stable at room temperature, slowly evolving H2S and H2 (and possibly Hp in air). Magnetic susceptibility data show that a low temperature transformation in 2H ... TaS2 (at so•K) is suppressed with the addition of hydrogen, and· at the same time the superconducting transition temperature T c rises from 0.8 to ~4.2•K at x = 0.11. Heat capacity measurements near this concentration show the superconductivity to be a bulk effect. Finally, by correlation of this data with susceptibility and T c measurements in other intercalation compounds, we suggest that the rise of T c (at low electron transfer) is due to suppression of the low temperature transformation and not due to an excitonic mechanism of superconductivity.


Properties Of Intercalated 2h-Nbse2, 4hb-Tas2 And 1t-Tas2, S. F. Meyer, R. E. Howard, G. R. Stewart, Juana Vivó Acrivos, T. H. Geballe Jan 1975

Properties Of Intercalated 2h-Nbse2, 4hb-Tas2 And 1t-Tas2, S. F. Meyer, R. E. Howard, G. R. Stewart, Juana Vivó Acrivos, T. H. Geballe

Juana Vivó Acrivos

The layered compounds 2H-NbSe, 24Hb-TaS, 2and 1T-TaS2 have been intercalated with organic molecules; and the resulting crystal structure, heat capacity, conductivity, and superconductivity have been studied. The coordination in the disulfide layers was found to be unchanged in the product phase. Resistance minima appear and the superconducting transition temperature is reduced in the NbSe2 complex. Conversely, superconductivity is induced in the 4Hb-TaS2 complex. Corresponding evidence of a large change of the density of states, negative for 2H-NbSe2 and positive for 4Hb-TaS2, was also observed upon intercalation. The transport properties of all the intercalation complexes show a pronounced dependence upon the …