Hydrothermal Brines: New Media for the Synthesis and Crystal Growth of Materials

Clemson University, Clemson SC

Investigators

Abstract

Non-Technical Summary This project explores new solid-state materials with potentially useful properties. The funding from the Solid State and Materials Chemistry Program supports continued development of a novel approach to synthesis of new materials, specifically a high temperature hydrothermal technique in which reactions are performed in water at exceptionally high temperatures (700 degrees C) and pressures (20,000 psi). These conditions are similar to those deep within the Earth, and often result in formation of high quality single crystals of new products. Such extreme reaction conditions are almost unknown in any other laboratories in the world. Because of this, compounds can be prepared that are completely new and unanticipated, and challenge existing theories of structure and bonding. Many of these unusual new materials have unexpectedly useful properties. Some can be used in lasers, ultrahigh resolution micromachining, new magnetic devices and possibly quantum communication and quantum computers. This research is directly applicable to one of the NSF Big Ideas: "The Quantum Leap: Leading the Next Quantum Revolution". The new techniques used in this program typically lead to crystals of exceptional size and quality, therefore they can be studied in greater detail than many other materials. The comprehensive investigation of these new crystal materials provides important insights into the next generation of new materials. Because the techniques employed in this research are used almost nowhere else in the world, the students in this program learn a unique skill set enabling them to stand out as the next generation of researchers. Technical Summary This program, funded by the Solid State and Materials Chemistry program in the Division of Materials Research, is a next-stage extension of high temperature hydrothermal synthesis as a route to new solid-state compounds. The primary emphasis in this project is on the investigation of a new class of mineralizers, namely hydrothermal brines. Brines are fluids containing concentrated salts like halides and carbonates. Such fluids have received almost no systematic laboratory study, but preliminary investigation suggests that they are excellent media for the synthesis and single crystal growth of an enormous new class of interesting compounds. The program focuses on open shell first row transition metal ions that are complexed by a range of oxyanion building blocks. These include vanadates, phosphates, germanates, gallates, stannates and other related building blocks containing a variety of structural and bridging characteristics. The new crystals exhibit a number of attractive physical properties including acentricity, polarity and frustrated magnetic behavior. The research targets specific types of compounds with these desirable properties for new piezoelectrics, multiferroics and similar materials. Because the synthesis techniques employed in this research are used almost nowhere else in the world, the students in this program learn a unique skill set enabling them to stand out as the next generation of researchers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.