  The increasing availability of a variety of two-dimensional materials has
generated enormous growth in the field of nanoengineering and nanomechanics.
Recent developments in thin film synthesis have enabled the fabrication of
freestanding functional oxide membranes that can be readily incorporated in
nanomechanical devices. While many oxides are extremely brittle in bulk, recent
studies have shown that, in thin membrane form, they can be much more robust to
fracture as compared to their bulk counterparts. Here, we investigate the
ultimate tensile strength of SrTiO$_3$ membranes by probing freestanding
SrTiO$_3$ drumheads using an atomic force microscope. We demonstrate that
SrTiO$_3$ membranes can withstand an elastic deformation with an average strain
of ~6% in the sub-20 nm thickness regime, which is more than an order of
magnitude beyond the bulk limit. We also show that these membranes are highly
resilient upon a high cycle fatigue test, surviving up to a billion cycles of
force modulation at 85% of their fracture strain, demonstrating their high
potential for use in nanomechanical applications.
