New superconduting cuprates with no effective doping: T'-(La3+)2-x(RE3+)xCuO4

Abstract

We report the synthesis of new superconducting cuprates T'-La2-xRExCuO4 (RE = Sm, Eu, Tb, Lu, and Y) using molecular beam epitaxy. The new superconductors have no effective dopant, at least nominally. The substitution of isovalent RE for La was essentially performed to stabilize the T' phase of La2CuO4 instead of the T phase. The maximum Tconset is ~ 25 K and Tczero is ~ 21 K. The keys to our discovery are (1) the preparation of high-crystalline-quality La-based T' films by low-temperature (~ 650C) thin film processes, and (2) more thorough removal of impurity oxygen at the apical site, which is achieved by the larger in-plane lattice constant (a0) of T'-La2-xRExCuO4 than other T'-Ln2CuO4 (Ln = Pr, Nd, Sm, Eu, Gd) with the aid of large surface-to-volume ratio of thin films.

10 pages, 5 figures (Proceedings of the 16th international symposium on superconductivity (ISS 2003), to be published in Physica C)

References in corpus (10)

• Progress and perspectives on the electron-doped cuprates
• New class of T-prime-structure cuprate superconductors
• Superconductivity phase diagrams of electron doped cuprates R(2-x)CexCuO4 (R = La, Pr, Nd, Sm, and Eu)
• Kondo effect in underdoped n-type superconductors
• Generic phase diagram of "electron-doped" T' cuprates
• Superconductivity in undoped T' cuprates with Tc over 30 K
• Superconductivity in undoped T'-RE2CuO4 with Tc over 30 K
• Role of impurity oxygen in superconductivity of "non-doped" T'-(La,RE)2CuO4
• Reduction dependence of superconductivity in undoped T' cuprates
• Intrinsic electron-doping in nominal "non-doped" superconducting (La,Y)${}_2$CuO${}_4$ thin films grown by dc magnetron sputtering

Cited by in corpus (12)

• Suppression of the antiferromagnetic pseudogap in the electron-doped high-temperature superconductor by "protect annealing"
• Strong electron correlation behind the superconductivity in Ce-free and Ce-underdoped high-Tc T'-cuprates
• Novel Electronic State and Superconductivity in the Electron-Doped High-Tc T'-Superconductors
• Optical study of superconducting Pr${}_2$CuO${}_x$ with $x\simeq 4$
• Pairing Symmetry Studied from Impurity Effects in the Undoped Superconductor T'-La${}_{1.8}$Eu${}_{0.2}$CuO${}_4$
• Electron-Doping Effect on Tc in the Undoped (Ce-Free) Superconductor T'-La1.8Eu0.2CuO4 Studied by the Fluorine Substitution for Oxygen
• Muon spin relaxation study of the spin correlation in the overdoped regime of electron-doped high-Tc cuprate superconductors
• Magnetism behavior of $T^{\prime }$-type Eu${}_2$CuO${}_4$ revealed by muon spin rotation/relaxation measurements
• Eliashberg analysis of the optical conductivity in superconducting Pr${}_2$CuO${}_x$ ($x\simeq 4$)
• Distinct variation of electronic states due to annealing in La${}_{1.8}$Eu${}_{0.2}$CuO${}_4$ and Nd${}_2$CuO${}_4$
• Cu-spin Correlation in the Electron-overdoped High-Tc Cuprate Thin Films of La_2-x_Ce_x_CuO_4_ Probed by Low-energy Muons
• Electronic State of T'-Pr${}_{1.3-x}$La${}_{0.7}$Ce${}_x$CuO${}_4$ ($x=0.10$) Studied by Compton Scattering