Advances in single crystal growth and annealing treatment of electron-doped HTSC

Abstract

High quality electron-doped HTSC single crystals of $\mathrm{P}{\mathrm{r}}_{2-\mathrm{x}}\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{Cu}{\mathrm{O}}_{4+\delta }$ and $\mathrm{N}{\mathrm{d}}_{2-\mathrm{x}}\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{Cu}{\mathrm{O}}_{4+\delta }$ have been successfully grown by the container-free traveling solvent floating zone technique. The optimally doped $\mathrm{P}{\mathrm{r}}_{2-\mathrm{x}}\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{Cu}{\mathrm{O}}_{4+\delta }$ and $\mathrm{N}{\mathrm{d}}_{2-\mathrm{x}}\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{Cu}{\mathrm{O}}_{4+\delta }$ crystals have transition temperatures $T_{\mathrm{c}}$ of $25$\,K and $23.5$\,K, respectively, with a transition width of less than $1$\,K. We found a strong dependence of the optimal growth parameters on the Ce content $x$. We discuss the optimization of the post-growth annealing treatment of the samples, the doping extension of the superconducting dome for both compounds as well as the role of excess oxygen. The absolute oxygen content of the as-grown crystals is determined from thermogravimetric experiments and is found to be $\ge 4.0$. This oxygen surplus is nearly completely removed by a post-growth annealing treatment. The reduction process is reversible as demonstrated by magnetization measurements. In as-grown samples the excess oxygen resides on the apical site O(3). This apical oxygen has nearly no doping effect, but rather influences the evolution of superconductivity by inducing additional disorder in the CuO${}_2$ layers. The very high crystal quality of $\mathrm{N}{\mathrm{d}}_{2-\mathrm{x}}\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{Cu}{\mathrm{O}}_{4+\delta }$ is particularly manifest in magnetic quantum oscillations observed on several samples at different doping levels. They provide a unique opportunity of studying the Fermi surface and its dependence on the carrier concentration in the bulk of the crystals.

19 pages, 7 figures, submitted to Eur. Phys. J. B

References in corpus (7)

• Quantum oscillations and the Fermi surface in an underdoped high-Tc superconductor
• Quantum Oscillations in the Underdoped Cuprate YBa2Cu4O8
• Shubnikov-de Haas oscillations in YBa_2Cu_4O_8
• A multi-component Fermi surface in the vortex state of an underdoped high-Tc superconductor
• de Haas-van Alphen oscillations in the underdoped cuprate YBa${}_2$Cu${}_3$O${}_{6.5}$
• Fermi Surface Evolution in an Electron-Doped High-Tc Superconductor Revealed by Magnetic Quantum Oscillations
• Role of oxygen in the electron-doped superconducting cuprates

Cited by in corpus (6)

• Magnetic Breakdown in the electron-doped cuprate superconductor Nd${}_{2-x}$Ce${}_x$CuO${}_4$: the reconstructed Fermi surface survives in the strongly overdoped regime
• Distribution of electrons and holes in cuprate superconductors as determined from ${}^{17}$O and ${}^{63}$Cu nuclear magnetic resonance
• Impact of the interface quality of Pt/YIG(111) hybrids on their spin Hall magnetoresistance
• ${}^{139}$La NMR investigation in underdoped La${}_{1.93}$Sr${}_{0.07}$CuO${}_4$
• Vortex Dynamics and Phase Diagram in the Electron Doped Cuprate Superconductor Pr${}_{0.87}$LaCe${}_{0.13}$CuO${}_4$
• Unravelling the glue and the competing order in superconducting cuprates