  Metal oxide resistive switches are increasingly important as possible
artificial synapses in next generation neuromorphic networks. Nevertheless,
there is still no codified set of tools for studying properties of the devices.
To this end, we demonstrate electron beam induced current measurements as a
powerful method to monitor the development of local resistive switching in TiO2
based devices. By comparing beam-energy dependent electron beam induced
currents with Monte Carlo simulations of the energy absorption in different
device layers, it is possible to deconstruct the origins of filament image
formation and relate this to both morphological changes and the state of the
switch. By clarifying the contrast mechanisms in electron beam induced current
microscopy it is possible to gain new insights into the scaling of the
resistive switching phenomenon and observe the formation of a current leakage
region around the switching filament. Additionally, analysis of symmetric
device structures reveals propagating polarization domains.
