Growth of epitaxial TlBaCaCuO a-axis oriented films on LaAlO3 buffer layers grown on SrTiO3 (100) substrates

a-Axis oriented films of the TlBaCaCuO family have been grown on LaAlO3 (100) buffer layers on SrTiO3 (100) substrates. The two step fabrication procedure involves the deposition of BaCaCuO(F) matrices through metal-organic chemical vapour deposition (MOCVD) and their annealing to yield the TlBaCaCuO phase through a thallium vapour diffusion process. The present unusual orientation, which to our knowledge is the first example of an a-axis orientation for this class of superconductors, is due to the nature of the LaAlO3 buffer layers deposited on SrTiO3 (100) substrates. The LaAlO3 films deposited in-situ via MOCVD from the new generation precursor La(hfa)(3) . diglyme (hfa=1,1,1,5,5,5-hexafluoro-2,4-pentanedione, diglyme=bis(2-methoxyethyl)ether) and Al(acac)(3) (acac=acetylacetone) an highly (100) oriented. The full widths at half maximum (FWHM) of the rocking curve of the (100) peak as small as 0.16 degrees have been observed.