materialsscienceandengineering: Tunable and mechanically robust ferroelectric ionic plastic crysta

materialsscienceandengineering:

Tunable and mechanically robust ferroelectric ionic plastic crystals

New research by a group from Hokkaido University in Japan has shown that the plastic ionic crystal, quinuclidinium perrhenate, has ferroelectric properties and can serve as a model for finding new plastic ionic crystals that demonstrate ferroelectricity with directional tunability. Their work appears in Nature Chemistry.

Ferroelectric materials are spontaneously polarizable. The polarity of ferroelectric materials can be reversed by placing the material in an inverted external electric field. This ability to switch the material’s polarity has been used for several applications including memory devices. Organic ferroelectric materials, in particular, are of interest because they are non-toxic and easier to make than their inorganic counterparts.

However, there are several obstacles to practical application of organic ferroelectric crystals. Each crystal in a substance can be polarized only along its polarization axis, which is dependent on the molecular dipole orientation within the crystal. For effective performance of ferroelectric materials, the polarization axis of the individual crystals in a substance must align in a particular direction. In contrast to the high symmetry seen in inorganic ferroelectrics, the low symmetry in organic crystals has made it difficult to fabricate ferroelectric materials with their polarization axes aligned in the desired direction.

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