ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Substitution of 3d elements Fe and Ni in the YBa2Cu3O7−δ superconductor was studied with the aim of understanding the role of substitution on the twin structure of the superconductor and the resultant microstructure on the pinning properties and Tc variation. The results of transmission electron microscopy (TEM), electron diffraction, and high-resolution electron microscopic studies (HREM) on the substituted samples of YBa2(Cu1−x,Mx)3O7−δ with M=Fe,Ni are reported here. TEM studies showed that the twin width decreases as x increases up to 0.015 for Fe substitution and is replaced by a 5-nm-size twin domain structure in the regime 0.015≤x≤0.05. This domain structure vanishes by x=0.12. HREM studies showed that these domains retain the orthorhombic structure of the unsubstituted sample contrary to the x-ray diffraction reports. In the case of Ni-substituted samples for x=0.05 the orthorhombic structure and the twin lamellas of the unsubstituted sample remain unaltered. The cooperative Jahn–Teller effect, limited in extent by the presence of Fe on the Cu(1) site, is proposed to be responsible for the formation of twin domains.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.343366
