PhD project: Magnetic Measurements to Probe Unconventional Superconductors

Project description

This project is based in St Andrews.

Magnetism and superconductivity are intimately connected in many so-called heavy fermion metals. A particularly dramatic case is URhGe, where two distinct superconducting regions exist - one coexisting with ferromagnetism, and the other at extremely strong applied magnetic fields that are sufficient to destroy conventional forms of superconductivity. This project will involve developing sensitive magnetic measurement apparatus that will operate at extremes of low-temperature an high-magnetic field, and apply them to study URhGe and other related materials. The aims are both to gain a deeper understanding of how magnetic pairing may lead to superconductivity and to drive the search for new superconducting materials. The apparatus in St Andrews includes a state-of-the-art dilution refrigerator (commissioned December 2007) with a base temperature 10 millikelvin and equipped with a 17 tesla magnet. The focus for the project is on magnetic measurements including torque magnetometry, field gradient magnetometry and a.c. susceptibility. By combining torque and field-gradient results, the vector magnetic moment can be determined as a function of magnetic field. This will give a complete phenomenological (Ginzburg-Landau) description of the magnetism in the region superconductivity occurs, and will provide detailed information about the nature of the magnetic interactions that are important for superconductivity. Another important component of the work will be to use quantum oscillations in the different measurements to study the Fermi surface and how it changes approaching and crossing quantum phase transitions.

Project supervisor

The project supervisor welcomes informal enquiries about this project.

Find out more about this research area

The links below summarise our research in the area(s) relevant to this project:

What next?

More PhD projects