We have used the unique spatial sensitivity of polarized neutron and soft x-ray beams in reflection geometry to measure the depth dependence of magnetization across the interface between a ferromagnet and an antiferromagnet. The net uncompensated magnetization near the interface responds to applied field, while uncompensated spins in the antiferromagnet bulk are pinned, thus providing a means to establish exchange bias.

Using coherent x-ray speckle metrology, we have measured the influence of disorder on major loop return point memory (RPM) and complementary point memory (CPM) for a series of perpendicular anisotropy Co/Pt multilayer films. In the low disorder limit, the domain structures show no memory with field cycling--no RPM and no CPM. With increasing disorder, we observe the onset and the saturation of both the RPM and the CPM. These results provide the first direct ensemble-sensitive experimental study of the effects of varying disorder on microscopic magnetic memory and are compared against the predictions of existing theories.

Resonant magnetic x-ray scattering from dense self-assemblies of 9-nm diameter -Co and hcp-Co particles is reported. For lower anisotropy ε -Co we find remanent magnetic scattering that is significantly enhanced, indicating preferred inter-particle moment orientations of both antiferromagnetic and ferromagnetic character. This interactionmediated collective behavior is consistent with dipolar fields and exists well above the isolated particles blocking temperature where thermal activation is operative, suggesting that magnetostatic super-spin waves exist in such systems. ε PACS: 75.25.+z, 75.50.Tt, 75.75.+a,

We have recorded magnetic speckle patterns of unprecedented quality on a tiny sample using soft-x-ray resonant magnetic scattering in reflection geometry. This geometry is well suited to the study of epitaxial thin films. The microscopic object consisted of an FePd wire with transversal stripe domains of alternatingly up and down magnetization. Sharp magnetic superstructure peaks reflect the domain periodicity, whereas the magnetic speckles give access to the domain morphology. A high degree of coherence has been obtained (␤ϭ0.85) as evidenced from the strong observed intensity fluctuations.