Experimental Evidence for an Atomic-like Parameter Characterizing the Systematics of Superconductivity in the Transition Metals
In a recently published paper1 we have presented experimental data on the superconducting critical temperature T c of amorphous transition metals (elements and alloys of neighboring elements) for the 4d and 5d series. We suggested that the data are consistent with the presence of a parameter first introduced by Hopfield,2 which characterizes the systematics of superconductivity in the transition metal (TM) series.‡ An unexpected result, however, is that the data indicate that this parameter η has a sharp triangular peak in the center of the d series at five d electrons per atom. This occurs for the 4d TM series at an electron-to-atom ratio e/a of 6.4. This behavior is contrary to the predictions of Bennemann and Garland,3 in which η has a smooth maximum on the right side of the TM series. In this paper we discuss other evidence, using data in the literature for the crystalline TM, indicating that η has a peak in the center of the 4d series.
KeywordsCohesive Energy Dielectric Response Function General Motor Research Laboratory Transition Metal Series Smooth Maximum
Unable to display preview. Download preview PDF.
- R.H. Hammond and M.M. Collver, LRL, University of California, Berkeley, UCRL-20500 (1970), p. 137.Google Scholar
- 3.K.H. Bennemann and J.W. Garland, in Superconductivity in d-and f-Band Metals, D.H. Douglass, ed. AIP Conf. Proc. No. 4, American Institute of Physics, New York (1972), p. 103.Google Scholar
- 6.J.M. Ziman, Principles of the Theory of Solids, Cambridge Univ. Press (1965), p. 129.Google Scholar
- 7.K.A. Gschneidner, in Solid State Physics, Vol. 16, Academic Press, New York (1964), p. 275.Google Scholar
- D.S. McClure, in Some Aspects of Crystal Field Theory, T.M. Dunn, D.S. McClure, and R.G. Pearson, Harper and Row, New York (1965), Chapter 4, p. 89;Google Scholar
- R.E. Watson and H. Ehrenreich, Comments on Solid State Physics Blll (1970).Google Scholar