Subcategory: Materials Science
John Montano - California State University San Bernardino
Co-Author(s): Gabriel Lopez, California State University, San Bernardino, CA ;Alessa Ibrahim, California State University, San Bernardino, CA
We have synthesized a new organometallic material that is predicted to be multiferroic. This material has an inexpensive and simple synthesis process. Ferroelectric materials can pave a way to exciting new technologies, such as FRAM which can change the industry of computing as we know it. Other applications include sonar, capacitors, ultrasound, and actuators. Bis(Diisopropylamonium) Cobalt(II) Tetrachloride, nicknamed BLUE, is grown from beaker solutions containing; molar solution Cobalt(II) Chloride Hexahydrate(237.93g/L), Hydrochloric Acid (HCL), and Diisopropylamine (DIPA). Blue has two known polymorphs, the easiest to obtain being needle like structures, and the time-consuming morphism of plates. Its density is 1.309 g/cm3 and melting point is above 130°C. Single crystal x-ray diffraction data gives its symmetry group is C 1 2 1. Dipole strength along each axis (a, b, c) respectively are -7.8541, 99.567, and -56.677 e-Å. The dipole strengths indicates the polar axis along a diagonal, predicted from theory to be 28° off the b-axis. Atomic Force Microscopy testing has shown ferroelectric and piezoelectric results on the b axis of needle crystals. Weak ferroelectric results are shown by Piezo Force Microscopy imaging and a process of “reading and writing” domains onto the samples. Reading and writing domains is a simple process of applying an external electric field from the cantilever to the sample, the electric field ranges from 0.1-1.5 Kv/cm, if the material is a ferroelectric the external electric field will polarize the domains of the sample, so when the sample is scanned again with no electric field the polarization will remain. Piezoelectric results are point tested with responses of 5-12 nA and qualitative hysteretic results. Bulk capacitance testing has shown “butterfly” curves that are common indications of piezoelectric responses for different samples of blue, and “lemon” shaped hysteresis curves due to resistance. Blue samples have shown piezoelectric responses when tested with an electric field that ranges between 5-15 Kv/cm. However, at the electric field of 11-15 Kv/cm the break down voltage of blue crystals is noted. Further testing is to be conducted on larger crystals and different axes with Atomic Force Microscopy and bulk capacitance testing.Not Submitted
Funder Acknowledgement(s): Funder Acknowledgments: Funding provided by NSF CREST Grant #1345163
Faculty Advisor: Dr. Tim Usher, email@example.com
Role: Atomic Force Microscopy and crystal synthesis. This encapsulates all piezo force microscopy testing done on the crystals along with various other AFM imaging. Crystal synthesis is making batches of crystals in order to grow bulk/large crystals for easier sample preparation and use.