"Magnetic Relaxation in Single Chain Magnets," April 26, 2013, 12n, MH 606

Thomas Gredig, California State University Long Beach

Magnetic interactions play a significant role in many modern applications.  The magnetic properties of many alloys have been characterized and studied in depth showing a broad array of interesting phenomena, which include the hardness, coercivity, saturation magnetization, and critical behavior near the transition point. Rather than finding new properties through exploring new materials, we show that properties of the material can be designed. For that purpose, we use a single chain magnet, called iron phthalocyanine, to form iron chains of different length, oriented in different directions. The iron chains are embedded in a carbon matrix and self-assemble on the substrate, when deposited via thermal evaporation.  We show that through design - tuning the length of the chain - properties, such as the coercivity, and magnetic relaxation can be selected. This system can have long magnetic relaxation times, where the remanent moment slowly decays. These results are compared to findings from spin-glasses.

This project is supported by National Science Foundation grant DMR-0847552.