Understanding and controlling the magnetism of nanometer-sized molecular systems are at the core of the Ames Laboratory Magnetic Molecules program. As the relevant magnetic interactions between atomic spin centers (usually a significant number of transition metal ions) are confined to a single molecule or to a low-dimensional molecule-based network, the observed magnetic phenomena are of a truly molecular origin. In our work we focus on both magnetically functionalized metal-oxo clusters and polynuclear coordination complexes. Because these molecules can be realized as single crystals and their structure and composition can often be systematically varied, they represent the systems of choice for the study of issues in nanomagnetism. The interdisciplinary Magnetic Molecules program couples complementary skills in synthesis chemistry, experimental, and theoretical condensed matter physics. The program specifically covers:

• Synthesis and chemical characterization of a vast variety of magnetic molecules, including isotopic enrichment and single-crystal growth.
• Specialized experimental techniques (low-temperature thermodynamic parameter characterization, magnetic resonance, and neutron scattering) aimed at a full characterization of all microscopic magnetic parameters.
• Development and application of analytical and computer simulational techniques for the determination of spectral, static and dynamic magnetic properties.

Work is guided by interest in a broad range of phenomena, e.g. low-temperature spin relaxation in nanomagnets, quantum tunneling of magnetization, topological quantum phase interference, frustrated spin ordering, magneto-optic properties, molecular magnetostriction, and metamagnetic transitions.