Scanning SQUID microscopy: A powerful tool for probing magnetism and superconductivity in complex oxides

Magnetic measurements are useful in investigating novel materials because they probe the behavior of electrons and their interactions. Superconducting Quantum Interference Devices (SQUIDs) are ultra-sensitive flux magnetometers and, when used in imaging mode, they become a powerful tool for mapping magnetic fields above a sample. This talk will outline the basics of scanning SQUID microscopy and highlight our recent measurements on a new material system: complex oxide interfaces. Our scanning SQUID technique uncovered the coexistence of superconductivity and magnetism in the LAO/STO oxide system. These measurements highlight many key benefits of the scanning SQUID technique including a 3 micron imaging kernel, excellent flux sensitivity, and an on-chip field coil to simultaneously measure both the intrinsic magnetism and the sample's response to an applied magnetic field.