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TT: Fachverband Tiefe Temperaturen
TT 23: Magnetic Heuslers, Half-Metals, Semiconductors, and Oxides (organized by MA)
TT 23.13: Vortrag
Montag, 16. März 2015, 18:15–18:30, H 1012
Neutron scattering studies of the field-induced magnetic phases of the Helimagnetic Spinel compound ZnCr2Se4. — •Alistair Cameron1, Dmytro Inosov1, Pavlo Portnichenko1, Maksym Surmach1, and Vladimir Tsurkan2 — 1Institut für Festkörperphysik, Technische Universität Dresden, 01069 Dresden — 2Universität Augsburg, 16135 Augsburg
ZnCr2Se4 is a magnetoelectric compound with a cubic spinel (m3m) structure. Magnetic materials with a spinel structure present a strong opportunity to study the interplay between spin, charge and orbital degrees of freedom in a topologically frustrated environment. Particularly, those exhibiting magnetoelectric effects are of particular interest. In zero applied field, the Cr3+ S=3/2 moments form an incommensurate magnetic ground state with a screw structure along the (001) direction with a TN of 20 K, which transforms into a spin spiral state in a magnetic field.
We have performed small angle neutron scattering (SANS) measurements on this spin structure for fields applied along the (100) and (110) directions. We find a field and temperature dependent structure for both field directions, with the reciprocal space propagation vector decreasing with increasing temperature and applied field, and showing a sharp jump in propagation vector across the domain selection transition. The phase diagram deduced by SANS for both field directions appear identical. In addition to investigating the AFM phase, we also probed the proposed spin nematic phase observing no SANS signal in this state, suggesting a lack of long range order.