Dynamical holographic Moirés in a TEM

Christophe Gatel (1) , Florent Houdellier (1) , Etienne Snoeck (1)

1 CEMES-I3EM - Interférométrie, In situ et Instrumentation pour la Microscopie Electronique

A new electron interferometry method has been developed and implemented in a transmission electron microscope to quantitatively analyse magnetic and electric properties emanating from objects using holograms free of artifacts and with a frequential sensitivity. This method, called dynamical holographic Moirés (DHM), is based on the double-exposure technique consisting in the superimposition of two different holograms. We improved this technique by acquiring the superimposed holograms for two well-defined excitation states of the sample and with a control of the superimposition frequency. The variations of magnetic and electrostatic fields between both excitation states can then be extracted directly from the amplitude part of the so-called interferogram. We demonstrate the efficiency of this method by studying quantitatively the magnetic field generated by a hard disk drive writing head excited by a DC and an AC current. Double exposure measurements have also been performed to study in situ electrostatic properties of a biased carbon nanocone tip. Our method opens the route to dynamical studies using the unique combination of nanoscale resolution and electromagnetic sensitivity of electron interferometry.

Domaines: Physique [physics]

Christophe Gatel, Florent Houdellier, Etienne Snoeck. Dynamical holographic Moirés in a TEM. Journal of Physics D: Applied Physics, 2016, 49 (32), pp.324001. ⟨10.1088/0022-3727/49/32/324001⟩. ⟨hal-01707046⟩