MOCVD Growth, Micro‐Structural, and Superconducting Properties of a‐Axis Oriented TlBaCaCuO Thin Films.

Abstract

2004 Superconductors Superconductors V 1500 MOCVD Growth, Micro-Structural, and Superconducting Properties of a-Axis Oriented TlBaCaCuO Thin Films. -Pure a-axis oriented Tl 2 Ba 2 Ca 1 Cu 2 O 8 superconducting thin films are deposited by a combined approach of MOCVD and Tl vapor diffusion on LaAlO3(100) buffer layers grown on SrTiO3(100) substrates. The a-axis oriented films may be used for preparing a particular type of Josephson's junctions, the so-called bi-epitaxial junctions. -(MALANDRINO, G.; PERDICARO, L. M. S.; FRAGALA*, I. L.; TESTA, A. M.; FIORANI, D.; Chem. Mater. 16 (2004) 4, 608-613; Dip. Sci. Chim., Univ. Catania, I-95125 Catania, Italy; Eng.) -W. Pewestorf 18-235

Metal–Organic Derivatives with Fluorinated Ligands as Precursors for Inorganic Nanomaterials

“…The films showed a homogeneous surface, although some rounded grains were also present as outgrowths with average dimensions ranging from 200 to 400 nm. The cross section indicated a thickness of about 300 nm for the sample deposited for 3 h. Similar behavior was observed for other multicomponent mixtures, such as [Ca­(hfac) 2 (tetraglyme)], [Ba­(hfac) 2 (tetraglyme)], and [Cu­(thd) 2 ] used for the deposition of BaCaCuO­(F) layers, precursor matrixes of the Tl 2 Ba 2 CaCu 2 O x films. , …”

“…The parent compound Ln 2 CuO 4+δ (Ln = Y, La) is an antiferromagnetic insulator (δ = 0), while superconductivity can be induced by partial modification of the formal copper oxidation state from +2 to +3 upon substitution of a divalent cation, such as Sr 2+ or Ba 2+ , for the trivalent La 3+ . The Ln 2−x Ba x CuO 4+δ (Ln = Y, La) films were efficiently grown on LaAlO 3 (100) and MgO (100) 475,476 The source of a group 2 metal in the above nanomaterials was the precursor [M(hfac) 2 (tetraglyme)]. Even though these precursors exhibit good volatility, they remain solid under most of the CVD conditions due to a slightly high melting point (e.g., 151°C for [Ba(hfac) 2 (tetraglyme)]).…”

“…The cross section indicated a thickness of about 300 nm for the sample deposited for 3 h. Similar behavior was observed for other multicomponent mixtures, such as [Ca-(hfac) 2 (tetraglyme)], [Ba(hfac) 2 (tetraglyme)], and [Cu(thd) 2 ] used for the deposition of BaCaCuO(F) layers, precursor matrixes of the Tl 2 Ba 2 CaCu 2 O x films. 475,476 The source of a group 2 metal in the above nanomaterials was the precursor [M(hfac) 2 (tetraglyme)]. Even though these precursors exhibit good volatility, they remain solid under most of the CVD conditions due to a slightly high melting point (e.g., 151 °C for [Ba(hfac) 2 (tetraglyme)]).…”