Properties of the electron-doped infinite-layer superconductor Sr1−xLaxCuO2

Abstract

Thin films of the electron-doped infinite-layer cuprate superconductor Sr1−xLaxCuO2 (SLCO) with doping x ≈ 0.15 were grown by means of pulsed laser deposition. (001)-oriented KTaO3 and SrTiO3 single crystals were used as substrates. In case of SrTiO3, a BaTiO3 thin film was deposited prior to SLCO, acting as buffer layer providing tensile strain to the SLCO film. To induce superconductivity, the as-grown films were annealed under reducing conditions, which will be described in detail. The films were characterized by reflection high-energy electron diffraction, atomic force microscopy, x-ray diffraction, Rutherford backscattering spectroscopy, and electric transport measurements at temperatures down to T = 4.2 K. We discuss in detail the influence of different process parameters on the final film properties.

Importance of grain-boundary Josephson junctions in the electron-doped infinite-layer cuprate superconductor Sr1−xLaxCuOTomaschko1, Leca2, Selistrovski3 et al. 2011Phys. Rev. BSelf Cite

“…28 We note that our values of I 0 R n and j 0 fall right onto the scaling line I 0 R n ∝ 1/ρ 1.5 n shown by Gross and Mayer 36 for YBCO GBJs, which was suggested to be related to the oxygen stoichiometry at the barrier. Thus, we speculate that our small I 0 R n product is a fingerprint of oxygen vacancies at the barrier due to vacuum annealing 26,27 of the as-deposited SLCO films, which would also be in line with the conclusions of Hilgenkamp and Mannhart. 14 The intrinsically shunted junction (ISJ) model 14,36 is based upon such barrier defects, which are supposed to form localized states.…”

“…Further details will be described elsewhere. 27 Four chips, each with seven junctions, have been fabricated and characterized. All SLCO GBJs showed comparable properties, which verifies reproducibility of our data.…”

Spin and charge excitations in artificial hole- and electron-doped infinite layer cuprate superconductors

“…IL cuprates are particularly interesting because of their crystallographic structure: the simplest among layered cuprates. On the other hand, the IL compounds are metastable and single crystal can be stabilized only in thin film form [23][24][25][26][27][28] .…”

Augmented methods for growth and development of novel multi-cation oxides

“…High T c values of 41 K have been reported by our group for infinite layer cuprates grown by MBE [5,6,14,15] or for bulk powder samples synthesized by high pressure synthesis methods (T c ≈ 43 K). While the superconducting transition temperatures of infinite layer cuprates grown by pulsed laser deposition (PLD) [16] or sputtering [17] are rather low with high resistivity values, nearly bulk-like T c is found for samples grown by MBE. In the case of thin film synthesis of infinite layer cuprates, several competing crystal structures, e.g., Sr 2 CuO 3 , Sr 14 Cu 24 O 41 , and orthorhombic SrCuO 2 , are impeding the synthesis of single phase samples [18] .…”

“…Sr 0.9 La 0.1 CuO 2 thin films grown with an RF power of 400 W show insulating behavior -partly due to the formation of IL-Sr 0.9 La 0.1 CuO 2+δ with a substantial amount of excess oxygen (δ ≈ 0.1). This phase is often referred to as "long-c" phase of IL-Sr 0.9 La 0.1 CuO 2+δ due to expanded c-axis lattice constant [16,19] when compared to the superconducting IL phase. We note that the usage of ozone as an oxidizing agent instead of atomic oxygen favors the formation of IL long-c phase.…”