The element specific magnetization and ordering in trilayers consisting of 0.3 -1.4 monolayer (ML) thick Fe layers embedded in Pd(001) has been determined using x-ray resonant magnetic scattering. The proximity to Fe induces a large moment in the Pd which extends ∼ 2 nm from the interfaces. The magnetization as a function of temperature is found to differ significantly for the Fe and Pd sub-lattices: The Pd signal resembles the results obtained by magneto-optical techniques with an apparent 3D to 2D transition in spatial dimensionality for Fe thickness below ∼ 1 ML. In stark contrast, the Fe data exhibits a 2D behavior. No ferromagnetic signal is obtained from Fe below the 2D percolation limit in Fe coverage (∼ 0.7 ML), while Pd shows a ferromagnetic response for all samples. The results are attributed to the temperature dependence of the susceptibility of Pd and a profound local anisotropy of sub-monolayered Fe.

We have fabricated ultra-thin disc shaped islands wherein shape anisotropy confines the moment to the island plane, creating XY-like superspins. At low temperatures, the superspins are blocked, and, as the temperature is increased, they undergo a transition into a superparamagnetic state. The onset of this dynamic superspin state scales with the diameter of the islands, and it persists up to a temperature governed by the intrinsic ordering temperature of the island material defining a range in temperature in which dynamic behavior of the magnetic islands can be obtained.

Abstract. Depth-dependent magnetism in MnSb(0001) epitaxial films has been studied by combining experimental methods with different surface specificity: polarized neutron reflectivity, X-ray magnetic circular dichroism (XMCD), X-ray resonant magnetic scattering and spin-polarized low energy electron microscopy (SPLEEM). A native oxide ∼4.5 nm thick covers air-exposed samples which increases the film's coercivity. HCl etching efficiently removes this oxide and in situ surface treatment of etched samples enables surface magnetic contrast to be observed in SPLEEM. A thin Sb capping layer prevents oxidation and preserves ferromagnetism throughout the MnSb film. The interpretation of Mn L 3,2 edge XMCD data is discussed.