摘要:

Single phase materials of RuSr2Gd0.5Eu0.5Cu2O8(Ru‐1212Gd0.5Eu0.5) and Ru(Sr1−xNax)2GdCu2O8(0 ⩽ x ⩽ 0.10) have been successfully synthesized in oxygen at 1065 °C. DC‐resistivity and magnetic susceptibility measurements show a decreases of the superconducting transition temperatureTcfrom 46 K in the pure Gd compound to 41 K in Ru‐1212Gd0.5Eu0.5, whereas the magnetic ordering temperatureTMdoes not change. The influence of the monovalent substitution Na+for Sr2+on the properties of Ru‐1212Gd is investigated and compared with previous work. Finally, the effects of Cu substituted RuSr2Gd(Cu1−xMx)2O8compounds, where M is Co, Ni and Ga for 0 ⩽x⩽ 0.03 are reported and compared with similar doping experiments in other high‐Tcsuperconductors. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1612401

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The general two‐electron wavefunctions obeying the Pauli exclusion principle and Anderson criteria for Cooper pairs are constructed for D2hand D4hsymmetries. It is shown that in axial symmetry groups the Blount theorem is violated and lines of nodes of triplet superconducting order parameter are required by the symmetry. Application of the results to high −Tcsuperconductors is discussed. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1612402

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The two‐dimensionalt‐Jmodel in a staggered field is studied by exact diagonalization up to 20 sites. For the low‐hole‐density region and a realistic value ofJ/t, it is found that the presence of a staggered field strengthens the attraction between two holes. With increasing field, the dx2−y2‐wave superconducting correlations are enhanced while the extended‐s‐wave ones hardly change. This implies that coexistence of the dx2−y2‐wave superconducting order and the commensurate antiferromagnetic order occurs in a staggered field. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1612403

出版商:AIP    

年代:1903

数据来源: AIP