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Symmetry engineering is explicitly effective to manipulate and even create phases and orderings in strongly correlated materials. Flexural stress is universally practical to break the space-inversion or time-reversal symmetry. Here, by introducing strain gradient in a centrosymmetric antiferromagnet Sr_{2}IrO_{4}, the space-inversion symmetry is broken accompanying a nonequivalent O p-Ir d orbital hybridization along the z axis. Thus, an emergent polar phase and out-of-plane magnetic moment have been simultaneously observed in these asymmetric Sr_{2}IrO_{4} thin films, which both are absent in its ground state. Furthermore, upon the application of a magnetic field, such polarization can be controlled by modifying the occupied d orbitals through spin-orbit interaction, giving rise to a flexomagnetoelectric effect. This Letter provides a general strategy to artificially design multiple symmetries and ferroic orderings in strongly correlated systems.

Magnetic-field-induced electric polarization in nanostructured multiferroic composite films was studied by using the Green's function approach. The calculations showed that large magnetic-field-induced polarization could be produced in multiferroic nanostructures due to enhanced elastic coupling interaction. Especially, the 1-3 type films with ferromagnetic nanopillars embedded in a ferroelectric matrix exhibited large magnetic-field-induced polarization responses, while the 2-2 type films with ferroelectric and ferromagnetic nanolaminates showed much weaker magnetoelectric coupling and lower magnetic induced polarization due to large in-plane constraint effect, which was in agreement with the recent observations.

We report a new kind of polyethlene oxide (PEO)-Li based composite polymer electrolyte containing active nanocomposite particles with ethylene carbonate (EC)/propylene carbonate (PC) plasticizers embedded in mesoporous SiO2 (EC/PC-SiO2). A very large enhancement of the ionic conductivity was observed for the PEO-Li/(EC/PC-SiO2) electrolytes. This could be attributed mainly to conducting EC/PC nanochannels in the active nanocomposite particles. This unique mechanism is absent in currently known nanocomposite polymer electrolytes with inert oxide nanoparticles. Both high ionic conductivity and excellent stability of such new nanocomposite polymer electrolytes potentially makes it one of the most promising electrolyte materials.

A giant low-frequency dielectric constant ( epsilon 0 approximately 10(5)) near room temperature was observed in Li,Ti co-doped NiO ceramics. Unlike currently best-known high epsilon 0 ferroelectric-related materials, the doped oxide is a nonperovskite, lead-free, and nonferroelectric material. It is suggested that the giant dielectric constant response of the doped NiO could be enhanced by a grain boundary-layer mechanism as found in boundary-layer capacitors. In addition, there is about a one-hundred-fold drop in the dielectric constant at low temperature. This anomaly is attributed to a thermally excited relaxation process rather than a thermally driven phase transition, as for that yielding ferroelectrics.