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Influence of Ni, Fe, and Zn substitution on the superconducting and antiferromagnetic state of YBa2Cu3O7−δ

K. Westerholt, H. J. Wüller, H. Bach, P. Stauche

DOI 10.1103/PhysRevB.39.11680 · Physical Review B

T1

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Abstract

We report magnetic and electric measurements on YBa2Cu3O7−δ with up to 15 at.% substitution of Ni, Fe, and Zn for Cu in the insulating state (δ≃1) and the metallic state (δ≃0.1). The concentration dependence of the Pauli susceptibility and the electrical conductivity indicates that the shift of the Fermi energy towards the mobility edge with increasing degree of substitution is one important mechanism for the suppression of the superconducting transition temperature. In the insulating antiferromagnetic state the Fe and Ni spins are very weakly coupled to the Cu spins. The Ni spins remain paramagnetic down to the lowest measuring temperature of 3 K, the Fe spins order at 5 K, independent of the Fe concentration. The Néel temperature depends weakly on the Fe and Zn concentration but decreases strongly with the Ni concentration. This different behavior reflects the different site preference for the substitution in the insulating state, namely Cu(2) for Ni and Cu(1) for Fe and Zn.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
YBa2Cu3O6.9

Archive — visibility unverified

Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

—Pressure not reportedunknown
YBa2Cu3O7-δ

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Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

—Pressure not reportedunknown

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