Spin and Dipole Ordering at Molecular Film Interfaces

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

In this project jointly funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division and the Electronic and Photonic Materials program of Materials Research division, Professor Peter A. Dowben at the University of Nebraska and Professor Ruihua Cheng at Indiana University Purdue University Indianapolis are combining molecules with large magnetic moments with molecules with large electric dipoles to create new materials with interesting spintronic properties. The goal is to achieve a molecular system where the magnetic properties can be altered by an applied electric field. If successful, the research will enable lightweight, high-speed, low-power electronic devices for a broad range of applications. This research brings together chemists, physicists, and material scientists to make and characterize the new materials. Student training includes international experiences in science for both undergraduate and graduate students, involvement in cutting edge research at the interface of chemistry and physics, and outreach activities where the students learn to communicate cutting edge research to a nontechnical audience. In more technical terms, a molecular magnetoelectric system is achieved by combinations of metal-organic compounds that demonstrate ligand control of the central metal spin state (spin crossover complexes) with ferroelectric polymers or zwitterionic, strongly dipolar molecules. One specific objective is to construct a thin-film molecular magneto-electric system where the magnetic properties of the molecular overlayer are altered by an applied electric field in either the ground state or the excited state. The starting point is the combination of an iron spin-crossover complex with the highly dipolar p-benzoquinonemonoimine zwitterion. The research project grows to include other spin crossover complexes in combination with a wide range of strongly dipolar molecules. Another objective includes the construction of a co-crystal heteromolecular structure in order to isothermally control switching between magnetic low-spin and high-spin states of selected molecules. The ultimate goal is to achieve voltage-controlled, magnetic moment-based devices of very small dimensions while delivering low-power, gigahertz, nonvolatile, local magneto-electric logic or memory operations with diminish latency time and much reduced power consumption. This project brings together investigations of fundamental interface chemistry, dipole coupling at hetero-molecular interfaces, the modeling of frontier orbitals, the fabrication of defined high-quality organic multilayers, and the characterization of magnetic induction with an applied electric field.