New Ferroelectric Material “Mel”

Undergraduate #285
Discipline: Physics
Subcategory: Materials Science

Joseph Martinez - California State University, San Bernardino
Co-Author(s): Tim Usher

The discovery of ferroelectric materials made way for the creation of important technology because of its ability to remember electric fields. This useful property allows for the creation of non-volatile computer memory. Piezoelectricity which is closely related to ferroelecticity is the ability of a material to convert mechanical energy directly into electrical energy. This property is applicable in many places such as energy harvesting and sensing pressures. A big problem with materials that are currently used today is that many of them are environmentally unfriendly, such as Lead Zirconate Titanate (PZT) or Barium Titanate (BTO). Computational chemists have been searching for a viable organic alternative to these materials, which turned up a promising compound codenamed “Mel”. Mel was grown by organic chemists in single crystal form, and with the use of an Atomic Force Microscope (AFM), we were able to measure the electrical response of a sample cut to 0.5mm thick while applying 40 volts. The electrical responses we are looking for is a hysteresis loop, and a butterfly curve, which are common indicators that the sample is a ferroelectric and piezoelectric material respectively. A hysteresis loop shows the samples dipoles will remain aligned after the electric field is removed, meaning that it remembered the electric field, and a butterfly curve shows us that there is a change in strain as the electric field is applied, meaning that there was a successful conversion between electrical and mechanical energy. Testing the sample with the AFM has given us both of these curves, supporting our hypothesis of this material being ferroelectric saturating at around 10 Volts, and having a displacement around 0.01nm.

Funder Acknowledgement(s): LSAMP NSF Grant #HRD1302873; National Science Foundation Award # 1345163; NASA Award # NNX11AQ99G; AFRL Contract # W911NF-12-1-0080

Faculty Advisor: Tim Usher,