Structural and magnetic characterization of evaporated Fe/Zr multilayers

Fe/Zr multilayers were prepared by alternate vapor deposition of pure Zr an d Fe at a rate of 0.1-0.2 nm s(-1) in a high-vacuum electron-gun evaporatio n system. The thickness of the constituent metals was varied from 1 nm to 1 2 nm controlled by an in situ quartz microbalance. The evaporated Fe/Zr fil ms were investigated by transmission electron microscopy for structural pro perties, Rutherford backscattering and X-ray diffraction for thickness and periodicity, and vibrating-sample magnetometer for magnetic characterizatio n. Experimental results showed that a rapid transformation from the polycry stalline to amorphous state in the iron layers occurred with decreasing Fe layer thickness in the Fe/Zr multilayers. The transformation was influenced by the Fe and Zr layer thicknesses and their thickness ratio in the films. The magnetization of the multilayers decreased significantly with decreasi ng Fe layer thickness, accompanying the amorphous Fe phase formation. The a morphous Fe in Fe/Zr multilayers still exhibited ferromagnetic behavior, an d the observed average magnetization was 0.41 mu(B) for Fe(1.0 nm)/Zr(9.0 n m) multilayers in a magnetic field of 10 kOe. The possible mechanisms respo nsible for these phenomena are also discussed.