Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 17: Correlated Electrons: Quantum-Critical Phenomena 1

TT 17.3: Talk

Tuesday, March 24, 2009, 14:30–14:45, HSZ 03

Polarized neutron tomography of Ni₃Al and Fe₂TiSn — •Andreas Neubauer¹, Michael Schulz¹, Christian Pfleiderer¹, Peter Böni¹, Anke Köhler², Nadja Wizent², and Günther Behr² — ¹Physik Department E21, Technische Universität München, D-85748 Garching, Germany — ²Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, PF270116, 01171 Dresden, Germany

The transition metal compounds Ni₃Al and Fe₂TiSn are weakly ferromagnetic metals, for which the magnetic properties are extremely sensitive to composition. We have attempted the growth of polycrystalline and single-crystal rods of these compounds with an UHV compatible image furnace. The polycrystalline starting material as well as the floating-zoned rods have been characterized by means of conventional bulk properties and EDX. As a new method we have additionally carried out polarized neutron tomography. The depolarization of the neutron beam proves to be extremely sensitive to tiny variations of the ferromagnetic transiton temperature, thus providing key information on the metallurgical phase diagram and the ideal growth conditions. The possible implications of our observations for the nature of quantum criticality in these compounds will be discussed.