Structural changes of high-Tc superconductors under pressures up to 29 GPa and at temperatures between 15 and 300 K
Abstract
Structural changes in the high-Tc superconductors YbBa2Cu3O7 (Yb-123) and Yb2BaCuO5 (Yb-211) with increasing pressure are studied using self-focusing X-ray equipment with a position-sensitive detector. The results show that Yb-123 has a bulk modulus of 155 GPa with linear compressibilities beta(a) = 0.0013/GPa, beta(b) = 0.0015/GPa, and beta(c) = 0.0033/GPa. The bulk modulus of superconducting Yb-211 is 170 GPa. Similar measurements on several other high-Tc superconductors and related materials show a systematic decrease of the bulk modulus of high-Tc superconductors when going from materials closely related to perovskite to materials with an extremely degenerated perovskite structure. This change is mainly caused by a change of the linear compressibility in the c-axis direction. The linear compressibilities in the a and b directions are similar for all these materials.
- Publication:
-
Fizika Nizkikh Temperatur
- Pub Date:
- May 1990
- Bibcode:
- 1990FizNT..16..615F
- Keywords:
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- Bulk Modulus;
- Crystal Structure;
- High Temperature Superconductors;
- Mixed Oxides;
- Pressure Effects;
- X Ray Diffraction;
- Copper Oxides;
- Crystal Lattices;
- Perovskites;
- Yttrium Oxides;
- Solid-State Physics