ABSTRACT:
Time-resolved in situ TEM studies can offer exclusive insight into dynamic material processes.  High spatial resolution and the ability to perform correlative diffraction and real-space imaging studies make TEM unique as a characterization tool.  While pump-probe techniques can offer picosecond temporal resolution with TEM, they are limited to studying highly reversible processes.  Nonreversible processes, such as crystallization, require all transformation information to be acquired at the rate the phenomenon of interest occurs.  In this talk, I will discuss the unique in situ TEM capabilities we have at the University of Minnesota for studying nonreversible processes. I will focus on the example of laser annealing amorphous yttrium iron garnet films on non-garnet substrates.  The in situ TEM crystallization studies were performed using a high speed camera which is limited to millisecond resolution.  To further push the temporal resolution of in situ TEM studies with our setup, single shot TEM capability in a lightly modified TEM with a small LaB6 cathode was also explored.