Hamburg 2001 – scientific programme

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AM: Magnetismus

AM 9: Poster: Magnetowid. (1-17), Dü. Schichten (18-34), Oberfl
ächenmag. (35,36), Mikr. Methoden (37-45), Mikromag. (46-58), Phasenüberg. (59-77), Spektroskop. (78-91), Nanokr.Mat.(92-96), Anisotrop. (97-101), Schmelzen(102-104),Sonst/postdeadl.(105-109)

AM 9.73: Poster

Tuesday, March 27, 2001, 14:45–19:00, Foyer S 3

[Fe(3ML)/V(13ML)]₂₀₀ - An antiferromagnet with reversibly and continuously tunable dimensionality? — •Vincent Leiner¹, Kurt Westerholt¹, Hartmut Zabel¹, and Björgvin Hjörvarsson² — ¹Institut für Experimentalphysik IV, Ruhr-Universität Bochum, D-44780 Bochum, Germany — ²Royal Institute of Technology, Materialphysics, S-100 44 Stockholm,

Previous work on the properties of FeV superlattices and their response to hydrogen (or deuterium) loading indicates a promising approach for the realisation of tuneable magnet: It is possible to grow FeV superlattices of very high structural quality which display an interlayer coupling of the FM Fe blocks across the non-magnetic V spacer layers; when exposed to a deuterium (D) atmosphere V - but not Fe - takes up deuterium in a reversible process that keeps the structural integrity of the sample intact; upon reduction of the thickness of the Fe layers to 3 monolayers (ML) MOKE and FMR show a vanishing in-plane anisotropy; finally, Fe(3ML)/V(13ML) superlattices exhibit an AFM coupling in the virgin state and an interlayer coupling constant, J’, that continuously decreases upon H uptake. Here we present neutron reflectivity data on a [Fe(3ML)/V(13ML)]₂₀₀ superlattice investigating the sublattice magnetisation, M, as a function of temperature and pressure of the ambient D atmosphere. Upon deuteration we find a continuous and reversible reduction of the ordering temperature, T_crit, and the critical exponent, β, consistent with a transition from a 3D AFM to a quasi-2D AFM as the ratio of interlayer coupling constant and intralayer coupling constant, J′/J, is steadily decreased.