MBE GROWTH OF COMPOUNDS ON THE COPPER RICH SIDE OF THE (SR,CA)CUO SYSTEM

Thins films belonging to the copper rich family in the (Sr,Ca)-Cu-O sy stem have been synthesized using Molecular Beam Epitaxy (MBE) depositi on. The growth conditions have been optimized on two different substra tes, MgO (100) and SrTiO, (100). We discuss in this paper the variatio ns of the electron diffraction pattern (RHEED) during the growth. The films obtained present a single orientation with good crystallization. The average composition measured by Rutherford Backscattering Spectro scopy (RES) is (Sr,Cn)(0.6)CuOz. This stoichiometry is close to the co mposition expected for the first members of the Spin Ladders homologou s series Srn-1Cun+1O2n. High resolution electron microscopy (HREM) and X-ray diffraction measurements on a four circles diffractometer are i n progress. Preliminary results confirm that the structure is consiste nt with spin-ladders structures. Typical room temperature resistivity is of the order of 0.5 m Omega cm. The search fof superconducting prop erties in these compounds is discussed.