Regensburg 2004 – wissenschaftliches Programm

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MA: Magnetismus

MA 12: Hauptvortr
äge Hütten / Bader

MA 12.2: Hauptvortrag

Dienstag, 9. März 2004, 14:30–15:00, H10

Confined Antiferromagnets** — •Samuel Bader — Materials Science Division 223, Argonne National Laboratory, Argonne, IL 60439, USA

Confinement on the nanoscale can give rise to new and interesting properties. In the present study the incommensurate antiferromagnetic spin density wave (SDW) structure of Cr is altered via interleaving in a superlattice geometry with a commensurate antiferromagnet (AF) in order to minimize interfacial roughness effects. Even though neither AF-layer exhibits hysteretic magnetic ordering, when put into proximity subtle hysteretic effects arise from the boundary conditions. Epitaxial Cr/Cr97.5Mn2.5(001) superlattices were studied via neutron scattering and transport measurements. The Mn doping creates a high Nèel temperature layer that confines the Cr SDW order. Transitions are observed with temperature cycling that show significant hysteresis when the number of SDW nodes within the Cr layer change by an odd number, while there is no hysteresis for changes of an even number of nodes. This results from the competition between maintaining the spin structure at the interfaces and introducing a spin slip at the nodes of the Cr SDW. * Supported by US DOE/BES-MS under contract W-31-109-ENG-38. **In collaboration with E.E. Fullerton, J.L. Robertson, A.E.R. Prinsloo, and H.L. Alberts.