Characterizing the performance of superconductors in the presence of magnetic fields is of critical importance not only for finding and optimizing materials for applications, but also for understanding and comparing basic properties in different classes of superconductors, ranging from conventional metallic, via high temperature cuprate and pnictide, to heavy fermion systems.

Using our unique He-3 MFM with vector magnet capabilities and a straightforward comparative method, we aim to directly probe the absolute value of the London penetration depth in a spatially resolved manner, as well as obtaining the absolute value of the pinning force for single Abrikosov vortices.

See, e.g., Kim, et al., Supercond. Sci. Technol. 25, 112001 (2012); Wulferding, et al., PRB 92, 014517 (2015).

Magnetic domain formation and exotic spin textures

The interplay between various degrees of freedom in correlated electron systems is the origin of rich phase diagrams, where oftentimes small details determine the occurrence of unexpected and exotic phases. While bulk magnetic characterization studies of such systems can give a hint about the kind of magnetic order, the actual domain structure remains elusive. Moreover, domain structures with similar fingerprints in thermodynamic measurements can differ dramatically.

Uncovering the microscopic magnetic structure and its field- and temperature behavior has important implications ranging from conceiving next-generation magnetic data storage devices to understanding the formation of exotic, topologically non-trivial phenomena, such as skyrmions.

See, e.g., Jeong, et al., PRB 92, 054426 (2015).