Oxygen control of dc-sputtered Bi2Sr2Ca1Cu2O8+δ films

Abstract

We report the preparation of Tc-optimized Bi2Sr2Ca1Cu2O8+δ thin films on SrTiO3 substrates using a planar dc-sputtering method. The oxygen content of these films is adjusted in situ by controlling the oxygen flow during sputtering. The oxygen content can be varied continuously from the overdoped state (Tc=72 K) to the condition with optimum oxygen content (Tc=88 K), and further, to the underdoped state (Tc=76 K). The oxygen content is determined by x-ray measurements of the c-axis lattice parameter.

BPSCCO Superconducting Films Grown by Spray Pyrolysis Technique: Systematic Study of the Relationship between Pb Content and Annealing Conditions

“…The discovery of high-T c superconductors has attracted much attention for their technological applications as bulk material as well as thin films, as for example, electronic devices, conductor tapes, and superconducting quantum interference devices. For the preparation of thin films, several physical and chemical techniques have been used: pulsed laser deposition [1], r. f. sputtering [2], magnetron sputtering [3], atomic layer epitaxy [4], chemical vapor deposition [5] and chemical deposition (spray pyrolysis) [6]. Most of them are high vacuum deposition techniques that produce superconductor thin films by sequential layer-by-layer deposition of the constituent elements.…”

Oxygen diffusion in off–c-axis normal-state Bi2Sr2CaCu2O8 + δfilms

“…For larger α, ρ deviates from the expected slope and decreases, indicating partly non-tilted film areas [9]. Due to refined film growth and annealing conditions [10], the films show excellent superconducting properties with T c0 values close to the maximum T c 88 K value of Bi 2 Sr 2 CaCu 2 O 8+δ films [11]. Even for tilted films usually characterized by somewhat reduced transition temperatures [8] high T c0 -values were observed,…”

Παρασκευη Και Μελετη Λεπτων Υμενιων Των Τριων Μελων Της Υπεραγωγιμης Σειρας Bi_2sr_2ca_n-1cu_no_2n+4n=123

“…Από τις πρώτες επιτυχείς προσπάθειες ήταν η παρασκευή μονοφασικού Bi-2223[86] (το έτος 1990) με θερμοκρασία μετάβασης Τ<;=95Κ, η οποία πραγματοποιήθηκε σε σύστημα «magnetron sputtering» με τη δημιουργία ενός ενδιάμεσου Sr 2 Ca n .iCu n 0 2 n+4 η= 1,2,3 ενώ επιπλέον, είναι σκόπιμη η εφαρμογή υψηλής θερμοκρασίας υποστρώματος, ώστε να μη σχηματίζονται μίγματα φάσεων. Έτσι η παρασκευή μονοφασικών υμενίων Βί-2212 με κρίσιμη θερμοκρασία T g =88K επιτεύχθηκε με την εναπόθεση «in-situ» από τους J. Auge et al[87] μετά από εκτεταμένη διερεύνηση, στις συνθήκες T"=860°C και P=3.5mbar(= : 2.7Torr) 0 2 , όπου μάλιστα χρησιμοποιήθηκαν υποστρώματα SrTi0 3(100). Όμοια, οι Ρ. Wagner et al[72] χρησιμοποίησαν P=2.9-3.1mbar καθαρού 0 2 και T"=830-840°C για την «in-situ» παρασκευή υμενίων Bi-2212 υψηλής κρίσιμης θερμοκρασίας Τ 0 =90Κ.…”