Electron Holography of the Magnetic Phase Shift of a Current-Carrying Wire

The controlled generation of magnetic fields to study switching processes in magnetic materials in the transmission electron microscope (TEM) is highly challenging [1-3]. Here, we use electron holography to study the magnetic field around a carefully fabricated current-carrying wire. As a result of the fact that a current flowing parallel to the plane of an untilted TEM specimen produces no net magnetic phase shift, we examine a short nano-fabricated segment of wire that is oriented parallel to the electron beam direction. Different regions of such a wire could in principle be used to apply either in-plane or out-of-plane magnetic fields to closely-adjacent nanomagnets.