LOW-FIELD GIANT MAGNETORESISTANCE IN (111)-TEXTURED CO AU MULTILAYERSPREPARED WITH MAGNETRON SPUTTERING/

A series of magnetron-sputtered [Co(1 nm)/Au(t(Au))](30) multilayers ( MLs) has been deposited on Si(100) substrates covered with a 100 nm th ick SiNx buffer layer. The samples were examined with x-ray diffractio n (XRD), magnetotransport (MR), isothermal magnetization (M-H), and tr ansmission electron microscopy (TEM) measurements. The quality of the interface and layer stacking in these MLs was observed with cross-sect ion TEM and examined with superlattice refinement of the XRD patterns, where an (111) preferred orientation is evident along the growth dire ction. Three MR maxima, with values Delta R/R-s = 3.5%, 1.3%, and 1.1% were observed for Au layer thicknesses (t(Au)) of 2.5, 3.9, and 5.1 n m, respectively, in a range of applied magnetic fields less than +/-10 0 Oe, that are attributed to the giant magnetoresistance (GMR) effect. In the [Co(1 nm)/Au(2.4 nm)](30) sample, the GMR coercivity is two or ders of magnitude less than that observed in epitaxial structures. Thi s makes the sputtered Co/Au MLs possible candidates for use in GMR app lications. Below t(Au) = 2 nm a maximum anisotropic MR effect of 2% is observed for t(Au) = 0.6 nm. (C) 1998 American Institute of Physics. [S0021-8979(98)05223-2].