Flexible Hall measurement system

• Subject Area: Electrical Engineering and Information Technology
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 511340083

The Hall effect appears in ferromagnetic materials as an anomalous Hall effect, where it is proportional to the z-component of the magnetization of a thin, ferromagnetic layer. It can be used to characterize the magnetization state of a magnetic layer system or even a magnetic microstructure. Various parameters of the magnetization curve of a device can be determined directly electrically, which are not or only with difficulty accessible with other techniques. Therefore, the characterization of magnetic thin film systems and devices with the anomalous Hall effect has become a standard technique in spintronics research. In the present proposal, the acquisition of a variable Hall effect measurement system for the "New Materials Electronics" working group at TU Darmstadt is proposed. The work of the working group is in the area of intermetallic materials for spintronics, antiferromagnetic spintronics and spin-orbit torques. The main components of the measurement system are a water-cooled electromagnet for magnetic fields up to 2T (at 20mm pole spacing), a custom cryostat for electrical measurements between 10K and 400K and measurement electronics for DC and AC lock-in measurements. The measurement system is deliberately designed to be open to respond flexibly to the various requirements of spintronics research. For example, the system will be suitable for using the anomalous Hall effect for standard characterization of magnetic thin films and microstructures, but also for studying the spin Hall effect and spin Hall magnetoresistance using planar Hall measurements, and for exploring the electrical switching of magnetization using the spin-orbit torques in complex multilayer systems at variable temperature. The open design of the electromagnet will also allow the installation of laser beam paths that enable magnetic characterizations using the magneto-optical Kerr effect. Thus, the variable Hall-effect measurement system applied for here will become a central working tool for the wide range of questions investigated by the research group.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Variables Hall-Messsystem
• Instrumentation Group: 0150 Geräte zur Messung der magnetischen Materialeigenschaften
• Applicant Institution: Technische Universität Darmstadt
• Leader: Professor Dr. Markus Meinert