In situ growth and superconducting properties of YNi2B2C thin films

Abstract

Thin films of the recently discovered intermetallic superconducting compound YNi2B2C have been grown in situ using a magnetron sputtering technique. High quality, c-axis oriented, films were obtained on MgO substrates held at about 800 °C during the sputtering process. The best films showed maximum Tc=15.25 K (onset), a transition width of ≊0.3 K, a room-temperature resistivity of 53±3 μΩ cm, a residual resistivity ratio up to ≊5.4, a low-temperature critical current Jc≊105 A/cm2 and Bc2≥6 T. Superconducting films were also obtained on sapphire and LaAlO3 substrates.

Transmission Electron Microscopy and High-Resolution Electron Microscopy Study of YNi2B2C Thin Film on Y2O3-Buffered MgO

“…On the other hand, high-quality thin films of R Ni 2 B 2 C are of great importance for the performance of several key experiments to understand the nature of the superconductivity in this class of compounds and to explore possible applications. YNi 2 B 2 C thin films have been prepared by several groups, using both sputtering , and pulsed laser deposition. , X-ray diffraction of YNi 2 B 2 C thin films on MgO repeatedly shows the existence of an Y 2 O 3 phase, , considered to result from the chemical reaction of deposited yttrium with oxygen released from the MgO substrate to produce an interfacial Y 2 O 3 layer. As a result of this uncontrolled formation of Y 2 O 3 , the stoichiometry of the borocarbide is affected, leading to the existence of impurity phases such as Ni 3 B and YNi 4 B within the films …”

SUPERCONDUCTING PROPERTIES OF LuNi2B2C THIN FILMS

“…LuNi 2 B 2 C thin films were also grown on sapphire by a magnetron sputtering technique already used to grow high quality YNi 2 B 2 C films [13] Stoichiometric LuNi 2 B 2 C targets were prepared at Saes Getters by arc melting. The substrates were placed "on axis" at 9cm from the target surface on a molybdenum heater held at 800-850°C and sputtered in pure argon at a growth rate of lnm/s (V=400V, I=1A).…”

Transmission Electron Microscopy and High-Resolution Electron Microscopy Investigation of the Microstructure of an YNi2B2C Thin Film

“…On the other hand, high-quality thin films are useful both for the study of particular physical properties and for the exploration of potential applications. 3 YNi 2 B 2 C thin films have been prepared by several groups, using both sputtering 4,5 and pulsed laser deposition. 3,6 Most of the investigations into YNi 2 B 2 C thin films have focused on film preparation and characterization; however, microstructural investigations by transmission electron microscopy (TEM) are still limited.…”