A series of c-axis oriented electron-doped high-Tc superconducting La(2-x)CexCuO4 thin films, from heavily underdoped x=0.06 to heavily overdoped x=0.19, have been synthesized by dc magnetron sputtering technique on (100) SrTiO3 substrates. The influence of various fabrication conditions, such as the deposition temperature and the deposition rate, etc., on the quality of the thin films has been scrutinized. We find that the quality of the films is less sensitive to the deposition temperature in the overdoped region than that in the underdoped region. In the phase diagram of Tc(x), the superconducting dome indicates that the optimally doping level is at the point x=0.105 with the transition temperature Tc0 = 26.5 K. Further more, both the disappearance of the upturn in the $ρ_{xx}$(T) curve at low temperature under H=10 T and the positive differential Hall coefficient, $R_H'=d ρ_{xy}/dH$, are observed around x = 0.15, implying a possible rearrangement of Fermi surface at this doping level.
We fabricated superconducting MgB2 thin films on (001) MgO substrates. The samples were prepared by magnetron rf and dc co-sputtering on heated substrates. They were annealed ex-situ for one hour at temperatures between 450°C and 750°C. We will show that the substrate temperature during the sputtering process and the post annealing temperatures play a crucial role in forming MgB2 superconducting thin films. We achieved a critical onset temperature of 27.1K for a film thickness of 30nm. The crystal structures were measured by x-ray diffraction.
We present a comprehensive study of molybdenum nitride (MoN) thin film deposition using direct current (DC) reactive magnetron sputtering. We have investigated the effect of various deposition conditions on the superconducting and electrical properties of the films. Furthermore, we have shown that meander-shaped single-photon detectors made from 5 nm MoN films have saturated quantum detection efficiency at the telecom wavelength of 1550 nm. Our results indicate that MoN may be a material of interest for practical applications of low-temperature superconductors, including single-photon detector…
The influence of the buffer layer of hafnia dielectric on superconducting properties of niobium nitride films, produced by the technique of the reactive magnetron depositing has been investigated for the first time. This study presents a comprehensive analysis of morphological, microstructural, and electrophysical parameters of thin NbN films.
We investigate the effect of annealing temperature on the crystalline structure and physical properties of tantalum-pentoxide films grown by radio frequency magnetron sputtering. For this purpose, several tantalum films were deposited and the Ta$_2$O$_5$ crystalline phase was induced by exposing the samples to heat treatments in air in the temperature range from (575 to 1000)$^\circ$C. Coating characterization was performed using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and UV-VIS spectroscopy. By X-ray diffraction analysis we found that a hexagonal Ta$_2$O$_5$ phase…
Superconducting Nb3Sn films were fabricated on sapphire and fine grain Nb substrates by magnetron sputtering from a single stoichiometric Nb3Sn target. The structural, morphological and superconducting properties of the films annealed for 24 h at temperatures of 800-1000 °C were investigated. The effect of the annealing time at 1000 °C was examined for 1, 12, and 24 h. The film properties were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. The DC superconducting properties of the films wer…
Superconducting properties of Nb$_{0.85}$Sc$_{0.15}$ film deposited by magnetron co-sputtering
Institute of Nanotechnology of Microelectronics, Russian Academy of Sciences（俄罗斯科学院微电子纳米技术研究所）；Dukhov All-Russia Research Institute of Automatics（杜霍夫全俄自动学研究院）；HSE University（高丽大学）
The effect of sputtering power ($P$=60 W-180 W) on the electrochromic properties of nickel oxide films deposited on ITO-coated glass substrates by the RF magnetron sputtering technique was investigated. Crystalline structure and morphology were assessed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The effect of sputtering power on electrochromism of the samples was evaluated with cyclic voltammetry and chronoamperometry. We used LiClO$_4$ in propilene carbonate solution for Li insertion/extraction. The chemical composition of the samples before and after Li …
Stoichiometry control of magnetron sputtered Bi$_2$Sr$_2$Ca$_{1-x}$Y$_x$Cu$_2$O$_y$ (0$\le$x$\le$0.5) thin film, composition spread libraries: Substrate bias and gas density factors
采用磁控溅射方法制备了Bi_2Sr_2Ca_（1-x）Y_xCu_2 O_y（0 ≤ x ≤ 0.5）中组分随空间变化的薄膜库。用合适的掩模共溅射了Bi_2Sr_2YCu_2 O_{8.5 + δ}和Bi_2Sr_2CaCu_2 O_{8 + δ}两种成分的靶。靶掩模在相反但共线的径向方向上产生线性变化，并且衬底台的旋转速度足以使原子紧密混合。EDS/WDS组成的薄膜的研究表明，耗尽的Sr和Bi，这是由于氧阴离子再溅射。耗尽在膜的中心处（即与靶同轴）最明显，并且对称地下降到75 mm衬底的任一侧。在膜的任一边缘处，化学计量匹配所需的比率。使用比例为2：1的氩气和氧气的12毫托工艺气体，校正锶损耗。通过采用旋转碳刷装置向样品基底提供-20 V DC偏压来消除铋耗尽。负衬底偏压已成功地用于增加腔室压力，以消除整个膜的再溅射效应。结果是具有所需化学计量的薄膜组成散布库。
In this paper we present a method for processing a hybrid Josephson junction on Co-doped BaFe2As2(Ba-122) single crystals with a thin film Pb-counter electrode and a barrier layer of TiOx. This includes the leveling and polishing of the crystals and structuring them with thin film techniques such as photo lithography, sputtering and ion beam etching (IBE). The junctions show hysteretical resistively and capacitively shunted junction (RCSJ)-like I-V characteristics with an IcRn-product of about 800uV.
The superconducting critical temperature (Tc > 15K) of niobium titanium nitride (NbTiN) thin films allows for low-loss circuits up to 1.1 THz, enabling on-chip spectroscopy and multi-pixel imaging with advanced detectors. The drive for large scale detector microchips is demanding NbTiN films with uniform properties over an increasingly larger area. This article provides an experimental comparison between two reactive d.c. sputter systems with different target sizes: a small target (100mm diameter) and a large target (127 mm x 444.5 mm). This article focuses on maximizing the Tc of the films an…
The effect of argon ion bombardment on the chemical properties of crystalline Ta$_2$O$_5$ films grown on Si(100) substrates by radio frequency magnetron sputtering was investigated by X-ray photoelectron spectroscopy. All samples were irradiated for several time intervals [(0.5, 3, 6, 9) min] and the Ta $4f$ and O $1s$ core levels were measured each time. Upon analysis at the surface of the films, we observe the Ta $4f$ spectrum characteristic of Ta$_2$O$_5$. Irradiated samples exhibit the formation of Ta suboxides with oxidation states Ta$^{1+}$, Ta$^{2+}$, Ta$^{3+}$, Ta$^{4+}$, and Ta$^{5+}$…
