X-ray-diffraction studies of Dy1.1Ba1.9Cu3O7−δ(001) and Dy1.3Ba1.7Cu3Oy(001) high-temperature-superconductor thin films

K. M. Choudhary; P. Seshadri; J. Bae

doi:10.1103/PhysRevB.45.4892

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X-ray-diffraction studies of Dy1.1Ba1.9Cu3O7−δ(001) and Dy1.3Ba1.7Cu3Oy(001) high-temperature-superconductor thin films

K. M. Choudhary, P. Seshadri, J. Bae

DOI 10.1103/PhysRevB.45.4892 · Physical Review B

T1

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Abstract

Single-phase Dy1+xBa2−xCu3Oy(001) thin films on LaAlO3(100) substrates were prepared by molecular-beam deposition and post annealing and they were studied by x-ray-diffraction (XRD) and resistivity measurements. The values of lattice constant c0 were determined after correcting for sample displacement errors in the XRD measurements. For an epitaxial Dy1+xBa2−xCu3Oy(001) film, which showed the onset of superconductivity at 53 K, the lattice constant c0 was determined as 11.592±0.018 Å. Similar superconducting behavior and same lattice parameter c0 have been observed for bulk Eu1.3Ba1.7Cu3Oy by Iwata et al. [Jpn. J. Appl. Phys. 26, L2049 (1987)]. Bulk Dy1Ba2Cu3O7−δ and Eu1Ba2Cu3O7−δ have almost the same lattice parameters. Hence the value of x in the Dy1+xBa2−xCu3Oy(001) thin film was derived as 0.3 (uncertainty=-0.03,+0.05). The Dy1.1Ba1.9Cu3O7−δ(001) thin film showed complete superconductivity at 89.5±0.5 K (critical transition temperature, Tc,0). Its lattice constant c0 was measured as 11.644±0.006 Å. Again, the composition was determined by comparison with lattice parameter (c0) and Tc,0 of bulk Eu1.1Ba1.9Cu3Oy as reported by Iwata et al. Since this film is a 90-K superconductor, it is labeled as Dy1.1Ba1.9Cu3O7−δ instead of Dy1.1Ba1.9Cu3Oy (uncertainty in the value of x=-0.03,+0.05).

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Dy1.3Ba1.7Cu3Oy Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	53	Pressure not reported	onset
Eu1.3Ba1.7Cu3Oy Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	53	Pressure not reported	unknown
Dy1.1Ba1.9Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	89.5	Pressure not reported	zero_resistance