Single Molecule Magnets

University Of California-San Diego, La Jolla CA

Investigators

Abstract

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor David N. Hendrickson to better control the quantum properties of single-molecule magnets (SMMs). The quantum tunneling of magnetization in monodisperse nanomagnets with well-defined structures prepared by chemical synthesis in solution at ambient temperatures will be investigated. The SMMs will be characterized by sensitive electron paramagnetic resonance methods, nuclear magnetic resonance (NMR) and magnetometry techniques. Goals of this research include: 1) synthesizing new SMMs in order to adjust the various factors controlling the nature of magnetization dynamics; (2) investigating the mechanism for the resonant quantum tunneling of magnetization (QTM); (3) pursuing the influence of intermolecular magnetic exchange interactions on QTM; (4) studying how the properties of SMMs change going from a molecule with a relatively large spin such as S = 13 to one with a small spin such as S = 4; (5) examining in detail spin parity effects exhibited by half-integer (e.g., S = 9/2, 13/2, etc.) spin SMMs; (6) preparing and characterizing new SMMs with transport properties; (7) attaching SMMs to functionalized metal surfaces or to polymers; (8) developing SMMs with photon accessibility; (9) preparing non-compensated spin SMMs doping S = 0 antiferromagnetic rings and polynuclear complexes; and (10) discovering why certain Mn12 SMMs exhibit magnetization tunneling with one-half the activation energy of other Mn12 SMMs. Single molecule magnets offer the potential for data storage on the nanoscale and other applications. This research is to develop new types of single molecule magnets and study the new quantum effects they present. Collaborations involve physics groups in three different countries and several chemistry groups, which will enhance the research training of a diverse group of graduate and undergraduate students.