Project Details
Projekt
Hall Measurement Set-up
Subject Area
Materials Science
Term
Funded in 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 544652129
In the Schierning group at the newly founded Research Center Future Energy Materials and Systems, extensive electrical transport characterization is important for practically all current and planned projects, especially Hall measurements. A Hall measuring set-up is urgently needed for this purpose. This will mainly be used to investigate changes in charge carrier density at martensitic phase transitions. In preliminary work, the decisive importance of changes in charge carrier density was demonstrated for the first time: In NiTi shape memory alloys, for example, the charge carrier density at the phase transition decreases by up to an order of magnitude. This can be interpreted as the formation of a charge density wave at the martensitic phase transition, for which there are currently many experimental indications, but as yet no "hard" evidence. Nevertheless, this already raises research questions with far-reaching consequences: Do charge density waves occur in shape memory alloys, specifically only here or in general? If not, how should the experimental signatures be interpreted? Do we see similar phenomena in other martensites? Can electronic aspects be taken into account in alloy design? Based on this, extensive work is currently planned, especially in collaborations. To support this work, the university has therefore prioritized this large-scale equipment application. The planned Hall measuring set-up will be used to investigate both non-magnetic and magnetic materials. The solid-state phase transitions to be investigated define the temperature range from 50 K to 400 K. Although higher temperatures would be desirable, they are unfortunately unrealistic from the point of view of the devices available on the market. Lower temperatures are not relevant for these alloys. Since magnetic materials are also to be investigated, this sets the magnetic field range at +3T to -3T - with lower fields, the normal and anomalous Hall effect cannot be reasonably separated. Due to the fact that the faculty does not have the possibility to recycle gaseous helium, it is absolutely necessary to procure a cryogen-free ("closed-cycle") device.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Hall-Messplatz
Instrumentation Group
0140 Magnetfeld- und -flußmeßgeräte (außer Geomagnetik 040)
Applicant Institution
Universität Duisburg-Essen
