UCLA researchers in the Department of Mechanical and Aerospace Engineering have developed novel methods for ferroelectrics control that allows for metastable remanent strain and permittivity states. The remenant strains and permittivity changes are achieved with a simple pulsed electric field producing substantial and stable changes in the strains and permittivities.
Current ferroelectric applications utilize linear ferroelectric properties from a polarized state so that when an electric field is applied, the piezoelectric strain and permittivity change linearly with the applied electric field. However, when the electric field is removed the strains and permittivity values return to their initial state. As a result, electrical power is required to maintain the new strain and permittivity states. This produces problems in many applications where long term changes are required or where power is a major issue.
Researchers at UCLA have developed a novel method to control metastable remnant properties in ferroelectrics, specifically in (011) oriented relaxor ferroelectrics by applying a pulsed electric field in a specific regime resulting in permanent strain and permittivity changes (i.e. the strain and permittivity states remain after release of the electric field). Further, by applying pulsed electric fields of different amplitudes, the remenant properties can tuned within a wide range of values.
Researchers have characterized and shown the ferroelectric properties on 0.5 mm thick (011) PMN-PT single crystal substrate. Researchers have shown proof of concept using tunable remanent strain in MR-MRAM device.
|United States Of America||Issued Patent||9,166,147||10/20/2015||2011-651|