Pressure-induced polarization reversal in multiferroicYMn2O5

Ferroelectric polarization reversal via successive ferroelastic transitions.

Switchable polarization makes ferroelectrics a critical component in memories, actuators and electro-optic devices, and potential candidates for nanoelectronics. Although many studies of ferroelectric switching have been undertaken, much remains to be understood about switching in complex domain structures and in devices. In this work, a combination of thin-film epitaxy, macro- and nanoscale pr...

Time reversal of cross-polarization in solid-state NMR

Dynamics of Polarization Growth and Reversal in PVDF Films

We present measurements of the time development of the dielectric displacement and the remanent polaroization in PVDF for poling times ranging from 1 ~s to 1000 s and poling fields between 0.8 and 2.0 MV /cm. For longer times (0.1 to 1000 s) we determined also the time dependence of the polarization distribution across the film thickness. After applying a steep rectangular HV pulse, the sample ...

Time-reversal of cross-polarization in nuclear magnetic resonance

It is demonstrated that the time evolution of the heteronuclear polarization-transfer process in a dipolar-coupled nuclear spin system can be reversed, leading to the observation of cross-polarization echoes. The cross-polarization echoes are induced by consecutive application of two pulse trains that produce effective Hamiltonians that differ only in sign. Cross-polarization echoes have been r...

Pressure-induced reversal between thermal contraction and expansion in ferroelectric PbTiO3

Materials with zero/near zero thermal expansion coefficients are technologically important for applications in thermal management and engineering. To date, this class of materials can only be produced by chemical routes, either by changing chemical compositions or by composting materials with positive and negative thermal expansion. Here, we report for the first time a physical route to achieve...