My research lab at Albion College is a diverse place, with chemistry, biology and athletic training majors all working together. It can be confusing and hectic but at the end of the day, we always have a lot of fun. There are three main areas of emphasis in my research lab: Magnetic Materials Research, Oenological Studies, and Student Designed Projects.
The development of the ENIAC in 1946 ushered the world into the computer age. With the subsequent introduction of the hard drive in 1956, we have relied on computers to organize and simplify our lives. The amount of information we ask our computers to keep track of has grown exponentially and hard drive capacity has thus far kept pace with these demands. During this time, we have also seen a concurrent decrease in the physical size of storage devices. As consumers’ appetites for higher memory devices grow unabated, we are fast approaching a stumbling block to further miniaturization of storage media. Traditional recording media rely on materials such as metals or metal oxides for their bulk magnetic properties. The presence of millions of atoms, each with several unpaired electrons create a large magnetic field capable of storing information. However, as you shrink recording media there comes a point where they are no longer magnetic and we are fast approaching this size limit. If we as consumers are going to continue to demand smaller and smaller storage devices, new technologies must be developed to create magnetic materials that overcome this size barrier.
Molecular-magnetic materials are one direction that researchers are looking to solve this problem. The magnetic properties of materials based on molecular magnets have the capacity to increase the density of information storage by a million fold. Instead of bulk characteristics, these materials rely on a single molecule to impart magnetic properties.
There have been several approaches to molecular-magnetic materials; one of the more promising approaches involves so-called hybrid materials composed of metal ions and organic radicals. On their own, organic radicals don’t possess enough correlated unpaired electrons to afford a large magnetic response. To overcome this deficiency, organic radicals are designed to coordinate to metal ions with multiple unpaired electrons. Ideally, the organic ligand will act as a ferromagnetic coupler (FC) and create a material with a large magnetic moment at room temperature. This strategy (shown in Figure 1) is based on one outlined by Dennis Dougherty and is called the “metal-radical” hybrid approach.
Figure 1: Scheme outlined by Dougherty to represent
high-spin magnetic materials. In the approach used in my lab, the arrows
represent transition metals with unpaired electrons and FC represents an organic
ligand with unpaired electrons.
The compounds I am using in my research are shown in Figure 2.
Compound 3 is an ideal organic linker because of two structure features: first, it has two unpaired electrons (shown as dashes) that can generate stronger magnetic fields and second, those unpaired electrons are in a position to bind to metals with even more unpaired electrons.
The work going on in my lab right now is looking to replace oxygen (O in compound 3) with nitrogen (N). This will increase the binding strength of the organic ligand towards metals and alter the magnetic properties of the organic linkers.
Information coming soon!
Information coming soon!
Updated 1/9/08 by Vanessa McCaffrey