Structure, stress, and magnetic properties of high saturation magnetization films of FeCo

Thin (/spl sim/2000 /spl Aring/) films of Fe/sub 60/Co/sub 40/ have been prepared by sputtering on Si/SiO/sub 2/, Si/AlO/sub x/, AlTiC/AlO/sub x/, AlTiC/AlO/sub x//NiFe, and AlTiC/AlO/sub x//NiFeCr substrates using an alloy Fe/sub 60/Co/sub 40/ target. The structure of the films was characterized by means of X-ray diffraction and transmission electron microscopy (TEM). Surface roughness was characterized by atomic force microscopy (AFM). Stress, transport, and magnetic measurements were conducted. We observed correlation in the following pairs of properties: coercivity-stress, grain size-stress, and coercivity-grain size. Although individual films had a stress in the wide range of compressive 2.5/spl times/10/sup 10/ Dyne/cm/sup 2/ to tensile 1.3/spl times/10/sup 10/ Dyne/cm/sup 2/, which depended to some degree on the material of the substrate and underlayer, we found that biaxial stress and coercivity seem to be described by a general trend, with coercivity being as low as 19 Oe at intermediate tensile stress and as high as 225 Oe at high compressive stress. The unstrained lattice parameter and Young's modulus of the alloy Fe/sub 60/Co/sub 40/ were also determined.