Structural and magnetic properties of Cr/Gd multilayers

The Cr/Gd multilayers (substrate/Mo/Crx/Gd30, where x = 10, 20, 30 A) were deposited on 200 A thick Mo buffer using molecular beam epitaxy (MBE) UHV technique. Two different types of monocrystalline substrates were used—MgO (1 0 0) and Al2O3 (1 1 −2 0). It was shown that the roughness of the Cr/Gd interface strongly depends on the type of the substrate—the samples grown on the sapphire substrate were smoother than those grown on MgO. A strong influence of substrate temperature on Cr/Gd interface formation was also observed—samples grown at room temperature have smoother interfaces than samples grown at 250 °C. The strong in-plane anisotropy has been observed from the hysteresis loop analysis. The magnitude of coercivity field was found to increase with increasing the Cr layer thickness. The Curie temperature dependence on Cr layer thickness was also investigated.