Superconducting (Sr, Nd) CuOy thin films with infinite-layer structure

Electric transport across Sr1−xLaxCuO2/Au/Nb planar

“…[7][8][9] To overcome this problem, epitaxially grown, single-crystal IL thin films have been fabricated, where the pressure is supplied by epitaxial strain. 10, 11 Karimoto et al 12 succeeded in synthesizing electron-doped IL thin films with T c close to the bulk value by molecular beam epitaxy (MBE) on KTaO 3 (KTO) substrates, supplying tensile strain, which is believed to support the electron-doping effect for the CuO 2 planes. Moreover, they confirmed that, under the oxidizing conditions generally used during deposition, vacuum annealing of the as-grown film is essential for superconductivity to emerge.…”

“…Without this reduction step, excess oxygen occupies interstitial sites in the Sr(L) planes and localizes electrons, which in turn hampers superconductivity. This reduction step was established in T compounds before 13 and is nowadays a common synthesis step for IL thin films grown by various techniques, such as sputtering, 11,14 pulsed laser deposition (PLD) 15,16 and MBE. 12,17 Yet, too strong reduction ends up in the formation of ordered oxygen vacancies in the CuO 2 planes.…”

Properties of the electron-doped infinite-layer superconductor Sr1−xLaxCuO2Tomaschko1, Leca2, Selistrovski3 et al. 2012Phys. Rev. B182100View full textAdd to dashboardCite

“…Therefore, as for T ′ -compounds 25 , a vacuum annealing step was introduced to remove excess oxygen and to induce superconductivity. Mean-while, this reduction step is commonly used for synthesis of superconducting IL films grown by numerous techniques, such as sputtering 26,27 , pulsed laser deposition (PLD) 20,21 and MBE 22,23 . However, too strong reduction generates oxygen vacancies in the CuO 2 planes and destroys superconductivity 22,27,28 .…”

“…However, too strong reduction generates oxygen vacancies in the CuO 2 planes and destroys superconductivity 22,27,28 . A secondary phase can be formed if the oxygen vacancies arrange in an ordered structure, referred to in literature as the "long c-axis" phase or "infinite-layer-related" (IL-r) phase 20,26,[29][30][31] . Its unit cell 2 √ 2a IL × 2 √ 2a IL × c s is a superstructure of the IL unit cell, where a IL is the in-plane lattice parameter of the IL structure and c s is the extended caxis parameter of the superstructure (with c s ∼ 3.6Å as compared to c IL ∼ 3.4Å).…”

Effect of adsorption time on structural, optical and electronic properties of SILAR deposited CuO thin films

“…Among the various semiconducting oxides the CuO is interested as it has p-type conduction and narrow band gap varying in between 1.2 and 1.6 eV. It has been widely used in photo diode [2], electrochromic devices [3], solar cells [4], catalysis [5], superconducting materials [6], field-emitting biosensors [7], gas sensors [8] and lithium ion batteries [9]. For the preparation of CuO thin films variety of methods, such as pulsed laser deposition [10], electro-deposition [11], spin coating [12], chemical vapour deposition [13], chemical bath deposition [14], and SILAR [15] methods have been used.…”