| Full text | |
| Author(s): Show less - |
de Lima, B. S.
;
da Luz, M. S.
;
Oliveira, F. S.
;
Alves, L. M. S.
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dos Santos, C. A. M.
;
Jomard, F.
;
Sidis, Y.
;
Bourges, P.
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Harms, S.
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Grams, C. P.
;
Hemberger, J.
;
Lin, X.
;
Fauque, B.
;
Behnia, K.
Total Authors: 14
|
| Document type: | Journal article |
| Source: | PHYSICAL REVIEW B; v. 91, n. 4, p. 9-pg., 2015-01-08. |
| Abstract | |
SrTiO3 undergoes a cubic-to-tetragonal phase transition at 105 K. This antiferrodistortive transition is believed to be in competition with incipient ferroelectricity. Substituting strontium by isovalent calcium induces a ferroelectric order. Introducing mobile electrons to the system by chemical nonisovalent doping, on the other hand, leads to the emergence of a dilute metal with a superconducting ground state. The link between superconductivity and the other two instabilities is a question gathering momentum in the context of a popular paradigm linking unconventional superconductors and quantum critical points. We present a set of specific-heat, neutron-scattering, dielectric-permittivity, and polarization measurements on Sr1-x Ca-x TiO3 (0 < x < 0.009) and a study of low-temperature electric conductivity in Sr-0.9978 Ca-0.0022 TiO3-delta. Calcium substitution was found to enhance the transition temperature for both antiferrodistortive and ferroelectric transitions. Moreover, we find that Sr-0.9978 Ca-0.0022 TiO3-delta has a superconducting ground state. The critical temperature in this rare case of a superconductor with a ferroelectric parent is slightly lower than in SrTiO3-delta of comparable carrier concentration. A three-dimensional phase diagram for Sr1-x Ca-x TiO3-delta tracking the three transition temperatures as a function of x and delta results from this study, in which ferroelectric and superconducting ground states are not immediate neighbors. (AU) | |
| FAPESP's process: | 09/54001-2 - Acquisition of cryogen-free equipment for the characterization of magnetic properties by vibrating sample magnetometry |
| Grantee: | Carlos Alberto Moreira dos Santos |
| Support Opportunities: | Multi-user Equipment Program |
| FAPESP's process: | 10/06637-2 - Crystalline structure and physical properties of the anomalous conductor KxMoO2-d |
| Grantee: | Leandro Marcos Salgado Alves |
| Support Opportunities: | Scholarships in Brazil - Doctorate |