  Ferroelectric devices use their electric polarization ferroic order as the
switching and storage physical quantity for memory applications. However,
additional built-in physical quantities and memory paradigms are requested for
applications. We propose here to take advantage of the multiferroic properties
of ferroelectrics, using ferroelasticity to create a remnant strain, persisting
after stressing the material by converse piezoelectricity means. While large
electric fields are needed to switch the polarization, here writing occurs at
subcoercive much lower field values, which can efficiently imprint multiple
remnant strain states. A proof-of-principle device, with the simplest and
non-optimized resistance strain detection design, is shown here to exhibit
13-memory states of high reproducibility and reliability. The related
advantages in lower power consumption and limited device fatigue make our
approach relevant for applications.
