X-RAY STRUCTURAL-ANALYSIS OF MULTILAYERED CO/NOBLE METAL-FILMS

Co/Pd and Co/Au multilayered structures were determined from a comparison between X-ray scattering measurements and calculations. Particularly, the calculation model, in which a fluctuation of lattice spacings in alloyed interlayers is taken into consideration, gives much better profile fittings than a fixed lattice spacing model. Multilayered structure was fabricated by a high quality periodicity, and scattering profile fittings revealed that the fluctuations of periodic thickness were less than 1 monolayer (ML) in both films. The fluctuation of periodic thickness Delta Lambda was 0.105 nm in Co/Pd and 0.110 nm in Co/Au, where Delta Lambda is a Gaussian distribution width of periodic thickness Lambda. The fluctuation of periodic thickness was nearly the same for the both films. On the other hand, the interlayer thickness was about 3.5 atomic layers in Co/Pd and about 2.0 atomic layers in Co/Au. The fact that the Co/Au film has much steeper interfaces than Co/Pd is explained by considering that Au and Co are a eutectic system while Pd and Co are an isomorphous system.