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Effective Masses in Zr-Doped Superconducting Ceramic SrTi
Phys. Rev. 178, 668 – Published 10 February, 1969
DOI: https://doi.org/10.1103/PhysRev.178.668
Abstract
An analysis is made of published experimental results on superconducting transition temperature as a function of carrier concentration and on magnetic field penetration depths in Zr-doped ceramic SrTi. From the penetration-depth results it is deduced that the ratio of effective masses and for 3% and 1% of Ti ions replaced by Zr satisfies if Zr ions are the main scattering centers. Using a model involving screened electron-electron interaction via intervalley phonons of energy 0.0497 eV modified by intervalley Coulomb repulsion and by intravalley effects, it is shown that the transition-temperature data can be fitted fairly well with mass changes of the above magnitude, provided that the ratio of phonon-induced to Coulomb intervalley interactions is postulated to increase by about 5% for each percent of Zr doping. It is argued that the large mass increases may imply that a crossing of levels associated with small and large mass states is taking place as Zr is added. The possibility of superconductivity at very low carrier concentrations in specimens with 3% Zr content is discussed.
References (28)
- J. K. Hulm, C. K. Jones, R. C. Miller, and T. Y. Tien, in Proceedings of the Tenth International Conference on Low-Temperature Physics (VINITI, Moscow, 1967), Vol. IIA, pp. 86-114
- D. M. Eagles, Phys. Rev. 145, 645 (1966)
- D. M. Eagles (to be published)
- J. F. Schooley and W. R. Thurber, J. Phys. Soc. Japan Suppl. 21, 639 (1966)
- P. G. de Gennes, Superconductivity of Metals and Alloys (W. A. Benjamin, Inc., New York, 1966), pp. 24-26
- A. H. Kahn and A. J. Leyendecker, Phys. Rev. 135, A1321 (1964)
- H. G. Reik, Z. Physik 203, 346 (1967)
- C. S. Koonce, M. L. Cohen, J. F. Schooley, W. R. Hosler, and E. R. Pfeiffer, Phys. Rev. 163, 380 (1967)
- J. Bardeen, L. N. Cooper, and J. R. Schrieffer, Phys. Rev. 108, 1175 (1957)
- D. M. Eagles, Phys. Rev. 164, 489 (1967)
- J. Appel, Phys. Rev. Letters 17, 1045 (1966) Bull. Am. Phys. Soc. 13, 426 (1968)
- H. Fröhlich, Advan. Phys. 3, 325 (1954) H. FröhlichPolarons and Excitons, edited by C. G. Kuper and G. D. Whitfield (Oliver and Boyd, Edinburgh, 1963)
- M. L. Cohen and C. S. Koonce, J. Phys. Soc. Japan Suppl. 21, 633 (1966)
- D. M. Eagles, J. Phys. Chem. Solids 25, 1243 (1964)
- W. G. Spitzer, R. C. Miller, D. A. Kleinman, and L. E. Howarth, Phys. Rev. 126, 1710 (1962)
- A. S. Barker, Jr., in Proceedings of the International Colloquim on Optical Properties and Electronic Structure of Metals and Alloys, Paris, 1965 (North-Holland Publishing Company, Amsterdam, 1966), p. 452
- V. L. Gurevich, A. I. Larkin, and Yu. A. Firsov, Fiz. Tverd. Tela 4, 185 (1962) [English transl.: Soviet Phys.—Solid State 4, 131 (1962)]
- A. S. Barker, Jr., Phys. Rev. 145, 391 (1966)
- W. L. McMillan, Phys. Rev. 167, 331 (1968)
- C. S. Koonce and M. L. Cohen, Phys. Rev. (to be published)
- E. Sawaguchi, A. Kikuchi, and Y. Kodera, J. Phys. Soc. Japan 17, 1666 (1962)
- H. P. R. Frederikse, W. R. Hosler, and W. R. Thurber, J. Phys. Soc. Japan Suppl. 21, 32 (1966)
- E. Ambler, J. H. Colwell, W. R. Hosler, and J. F. Schooley, Phys. Rev. 148, 280 (1966)
- H. P. R. Frederikse and G. A. Candela, Phys. Rev. 147, 583 (1966)
- N. N. Bogoliubov, V. V. Tolmachev, and D. V. Shirkov, A New Method in the Theory of Superconductivity (Academy of Sciences, Moscow, USSR, 1958)
- J. Labbé, S. Barišić, and J. Friedel, Phys. Rev. Letters 19, 1039 (1967)
- B. A. Tavger and V. Ya. Demikhovskii, Zh. Eksperim i Teor. Fiz. 48, 748 (1965) [English transl.: Soviet Phys.—JETP 21, 494 (1965)]
- J. Lindhard, Kgl. Danske Videnskab. Selskab, Mat. Fyz. Medd. 28, 8 (1954)