Off-axis MgB2 films using an in situ annealing pulsed laser deposition method

Authors

Yue Zhao, University of WollongongFollow
Mihail Ionescu, Australian Nuclear Science and Technology OrganisationFollow
Josip Horvat, University of WollongongFollow
S X. Dou, University of WollongongFollow

RIS ID

13673

Publication Details

Zhao, Y, Ionescu, M, Horvat, J, & Dou, SX (2005), Off-axis MgB2 films using an in situ annealing pulsed laser deposition method, Superconductor Science and Technology, 18, pp. 395-399.

Abstract

Highly smooth and c-axis oriented superconducting MgB₂ thin films were prepared by pulsed laser deposition (PLD) with off-axis geometry. The films were deposited on Al₂O₃–C substrates perpendicularly aligned to a stoichiometric MgB₂ target in a 120 mTorr high purity Ar background gas. An in situ annealing was carried out at 650 °C for 1 min in a 760 Torr Ar atmosphere. Despite the short annealing time, an x-ray θ–2θ scan shows fairly good crystallization, according to the clear c-axis oriented peaks for the films. Both atomic force microscopy and the x-ray diffraction results indicate that the crystallite size is less than 50 nm. The root mean square roughness of our off-axis film is nm in a 5 × 5 µm² area. The T_{c onset} value of the best off-axis film reaches 33.1 K with a narrow transition width of 0.9 K. The films showed no anisotropy in H_{c 2}–T curves when parallel and perpendicular fields were applied. The slope of the H_{c 2}–T curves in the low field regime is 1 T K⁻¹, which is among the highest reported values.