Dresden 2014 – scientific programme
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MA: Fachverband Magnetismus
MA 42: Magnetic Materials III
MA 42.5: Talk
Thursday, April 3, 2014, 16:00–16:15, HSZ 04
Long range incommensurable spin ordering in a swedenborgite compound — •Johannes Reim1, Martin Valldor2, and Werner Schweika1 — 1Jülich Centre for Neutron Science JCNS-2 and Peter Grünberg Institut PGI-4, Forschungszentrum Jülich, Jülich, Germany — 2II. Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany
The new swedenborgite compound family (P63mc) displays similarly to the pyrochlores a highly frustrated
network of tetrahedral coordinated magnetic ions. However, its broken inversion symmetry raises further the complexity of ordering due to non-vanashing DM interactions. Recently investigated materials of this family show various signs for unusual geometric frustration. In compounds with magnetic Co and Fe ions, where single crystals are available like CaBaCo2Fe2O7, we observed an antiferromagnetic ordering below TN≈160 K, which, however, turned out to be rather complex. Diffuse neutron scattering at DNS (FRM II) has revealed a magnetic order in a three times larger supercell. A particular intriguing result was the chiral interference observed apparently as an asymmetry of the magnetic Bragg intensities.
Further powder diffraction experiments at POWGEN (SNS) with higher resolution evidenced additional satellite peaks close to the main magnetic peaks, with a propagation vector τ=0.016 Å−1 corresponding to a long periodicity of about 400 Å.