Imaging of Condensed Matter Magnetism Using an Atomic-Sized Sensor

Abstract

The development of increasingly sensitive scanning techniques has enabled valuable insights into the physics of interacting condensed matter systems. Recently a new kind of local probe based on Nitrogen-Vacancy (NV) centers in diamond has emerged as a powerful magnetic imaging platform. The NV center has been used for a variety of local measurements including measurements of magnetic fields, imaging of single electron spins with nanometer resolution, magnetic resonance detection of single nuclear spins, as well as measurements of temperature and electric fields. However, imaging an a priori unknown static magnetization structure using a NV center magnetometer is inherently difficult because infinitely many magnetization patterns can produce identical local magnetic fields. In this work I use a scanning NV center magnetometer to image topologically non-trivial magnetization patterns in stacks of thin magnetic films, in which skyrmions had been predicted. I will summarize the details of the experiment crucial to obtaining these data as well as our method for extracting the underlying magnetization structure. As a result of this experiment, we discover a never-before observed type of skyrmion tube whose structure rotates from top to bottom, which has since been confirmed by another technique.