ISSN:
1573-7357
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Westudied T c of Y Ba 2 Cu 3 O x (Y123), Y 0.89 Ca 0.11 Ba 2 Cu 3 O x (YCa123) and NdBa 2 Cu 3 O x (Nd123) single crystals with various oxygen contents x. Compared to T c (x) of Y123 the T c (x) curves of YCa123 are shifted to lower oxygen contents and the maximum transition temperature T c,max decreases with increasing Ca content whereas in Nd123 T c (x) is shifted to higher oxygen contents and T c,max is increased. According to the universal parabolic T c (n h ) behavior the differences in T c (x) of Y123, YCa123 and Nd123 can be ascribed to different hole concentrations n h in the CuO 2 planes caused by doping via changes in chemistry or structure. In order to study the influence of structural changes on T c we examined the hydrostatic pressure effect dT c /dp (p ≤0.6GPa). In the underdoped region, at n h ≈0.11, the examined compounds show a peak in dT c /dp which is very pronounced for systems with well ordered CuO chains. As this peak occurs at the same n h in all investigated systems it is not caused by oxygen ordering, but its origins might be found in a strong influence of lattice deformations on the electronic structure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022559025868
