STRUCTURE AND MAGNETIC PROPERTIES IN MAGNETIC MULTILAYERS. Z.H. Mai, Y.S. Gu, G.M. Luo, M.L.Yan and W.Y.Lai, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China

Ultrathin magnetic multilayers with non-magnetic 4d-metal spacer Fe/Ag, Fe/Mo, Fe/Pd and Co/Pd grown by RF sputtering were studied combined X-ray small reflections, high angle diffraction, X-ray diffuse scattering, resistance measurement and vibration sample magnetometer. The results show that the magnetic properties of the magnetic multilayers are strongly structural dependent.

Ultrathin magnetic multilayers consisting of alternate layers of a magnetic metal separated by layers of a non-magnetic metal have profound signifi-cance in science and potential in applications. Since the first observation of giant magnetoresistance (GMR) effect in Fe/Cr multilayers by Baibich et al., great advances have been made in understanding of the subject.

The structural parameters of Co/Pd and Fe/Ag, Fe/Mo, Fe/Pd multilayers such as the periods, the interfacial roughness, the interplane distances and the grain sizes have been determined. In the Fe/Pd system, the densities of multilayers change abruptly with Pd layer thickness increase. The crystal structure of Fe layer changed from bcc to fcc when the Pd layer thickness t_Pd ( 3.6nm.. In the Co/Pd system, the interfacial roughness increases from 0.2nm to 1.2nm as the Pd layer thickness t_Pd increases from 1nm to 6.4 nm. The saturate magnetization of Co/Pd multilayers oscillate with the Pd layer thickness. Structural abnormalities were found with nominal Pd layer thickness of 2.56nm and/or 1.28nm.

GMR effects in sputtered Fe/Ag and Fe/Mo multilayers were observed in first time. Both GMR and interlayer coupling of the adjacent magnetic layers possess the same periods which are 1.1nm for Fe/Ag and 1.2nm for Fe/Mo. The results suggest that the relatively rough interfaces and moderately thin Fe layer thickness are the key factors for enhancing GMR in the sputtered films.