High quality c-axis oriented films of the intriguing intermetallic superconducting compound YNi2B2C have been obtained "in situ" by magnetron sputtering on MgO substrates held at about 800 °C. The films showed maximum Tc = 15.3 K, ΔTc = 0.1 K, room temperature resistivity ρ ≈ 50 μΩ·cm, critical current Jc ≈ 105 A/cm2 and BC2 ≈ 6 T. Superconducting films were also obtained on Al2O3 and LaAlO3 single-crystal substrates. From the ρ(T) dependence a value of the Debye temperature ΘD = 330 ± 20 K can be deduced. At low temperatures the resistivity follows a quadratic power law possibly indicative of a high value of the electron-phonon interaction parameter λ. In order to clarify the role of λ in these compounds, point contact spectroscopy measurements have been performed on YNi2B2C and HoNi2B2C bulk samples prepared by inductive melting using a Low Temperature Scanning Tunneling Microscope (LTSTM). In the point contact regime clear evidence of a superconducting gap have been found in both compounds, corresponding to a moderate strong coupling behaviour (2Δ/KTC ≈ 3.8). © 1997 Plenum Publishing Corporation.
Re-Ni2B2C Superconducting borocarbides: "in situ" growth of thin films, transport and point contact spectroscopy / Andreone, A.. - In: JOURNAL OF LOW TEMPERATURE PHYSICS. - ISSN 0022-2291. - 107:5-6(1997), pp. 527-532. [10.1007/BF02397237]
Re-Ni2B2C Superconducting borocarbides: "in situ" growth of thin films, transport and point contact spectroscopy
Andreone A.
1997
Abstract
High quality c-axis oriented films of the intriguing intermetallic superconducting compound YNi2B2C have been obtained "in situ" by magnetron sputtering on MgO substrates held at about 800 °C. The films showed maximum Tc = 15.3 K, ΔTc = 0.1 K, room temperature resistivity ρ ≈ 50 μΩ·cm, critical current Jc ≈ 105 A/cm2 and BC2 ≈ 6 T. Superconducting films were also obtained on Al2O3 and LaAlO3 single-crystal substrates. From the ρ(T) dependence a value of the Debye temperature ΘD = 330 ± 20 K can be deduced. At low temperatures the resistivity follows a quadratic power law possibly indicative of a high value of the electron-phonon interaction parameter λ. In order to clarify the role of λ in these compounds, point contact spectroscopy measurements have been performed on YNi2B2C and HoNi2B2C bulk samples prepared by inductive melting using a Low Temperature Scanning Tunneling Microscope (LTSTM). In the point contact regime clear evidence of a superconducting gap have been found in both compounds, corresponding to a moderate strong coupling behaviour (2Δ/KTC ≈ 3.8). © 1997 Plenum Publishing Corporation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
