This award from the Chemistry Research Instrumentation Program and the National Facilities and Instrumentation Program will help the Department of Chemistry at Columbia University acquire a SQUID based magnetometer. Among the areas of chemical research that will be enhanced by the acquisition are the following: (1) investigations of the transition temperatures and critical current densities of metal-substituted and oxygen doped high-temperature copper oxide superconductors; (2) studies of the effects of metal substitution on the charge density wave and superconducting states in transition metal dichalcogenide materials; (3) measurements of radical yields and investigations of radical pair interactions in the photolysis of ketones on porous solids; and (4) studies of magnetism in novel high-spin and chiral organic solids. A magnetometer measures the force a material experiences when subjected to a magnetic field gradient. A paramagnetic substance consists of molecular magnetic dipoles which tend to orient themselves parallel to the direction of the field. The lining up of the magnetic dipoles is opposed by the thermal motion of the particles, and in a paramagnetic substance at room temperature only a small fraction of the molecules have their magnetic moments aligned with the field. The measurement of the volume magnetic susceptibility is positive for paramagnetic substances and negative for diamagnetic substances. The magnetometer is useful in studying high temperature superconducting materials, radical yields, and research dealing in solid state chemistry.
