New Scanning Probes for Nanomagnetic Imaging

I will discuss recent experiments in our group aimed at developing and applying two promising new magnetic scanning probes.

The first probe is based on newly developed nanowire (NW) force sensors, which have recently enabled a form of AFM capable of mapping both the size and direction of tip-sample forces.  I will present first results in which we functionalize such NWs with nanometer-scale magnetic tip and characterize their behavior.  Using these NW sensors, we intend to realize a form of vectorial MFM capable of mapping stray magnetic fields with enhanced sensitivity and resolution compared to the state of the art.

The second scanning probe consists of a sharp quartz tip with a nanometer-scale superconducting quantum interference device (SQUID) integrated on its end.  This SQUID-on-tip (SOT) sensor achieves record sensitivity to both stray magnetic flux and local thermal dissipation. I will discuss experiments using this device to map the stray magnetic field produced by individual nanomagnets and superconducting vortices.
The unique capabilities of both of these scanning probes may provide new types of imaging contrast for in a variety of physical systems.  These include nanometer-scale magnetic structures such as domain walls, magnetic vortices, and magnetic skyrmions.  The ability to map mesoscopic current flow in two-dimensional materials and topological insulators or image magnetic field produced by superconducting films and nanostructures could shed light on a number of open questions. 

Bio: Martino Poggio received his B.A. in physics from Harvard University in 2000 and his Ph.D. from the University of California, Santa Barbara in 2005. In graduate school he worked for Prof. David Awschalom on ultrafast optics and semiconductor spintronics. After receiving his doctorate, he started work as a post-doctoral fellow at the Center for Probing the Nanoscale, a joint center between Stanford University and IBM Corporation funded by the National Science Foundation. Until late 2008 he worked in this capacity in Dr. Dan Rugar’s lab at the IBM Almaden Research Center in San Jose, CA on high sensitivity nuclear magnetic resonance force microscopy. In January of 2009, he started work as Argovia Assistant Professor in the Department of Physics at the University of Basel. In 2014, he was promoted to Associate Professor. Prof. Poggio is a winner of a 2013 ERC Starting Grant and a member of the American Physical Society