ENDOR and ESR at IUS

 

This equipment, which was acquired in 2004 from a retiring professor at Purdue, consists of an entire ENDOR laboratory. That stands for Electron Nuclear Double resonance. Basically, the process consists of simultaneously carrying out Nuclear Magnetic Resonance (NMR) and Electron Spin Resonance (ESR). So you need to have a radio frequency (RF) source (for the nuclei spin transitions) , as well as a microwave source ( for the electron spin transitions). In general, an ESR peak is found and then a sweep is made in the RF looking for changes in the ESR signal (which indicate an NMR transition).  The work is generally done at liquid nitrogen temperatures, or even liquid helium temperatures. Low temperatures are necessary in order to reduce spin relaxation times. This equipment has been used to study semiconductor crystals, specifically CdTe, doped with Mn. The ENDOR technique allows high sensitivity detailed studies of the bond structure of various materials, giving information that is presently inaccessible (or inaccurate) by any other methods. Both the Fermi Contact interaction coefficients and the Hyperfine coefficients can be measured precisely. 

 

If the equipment is ever fully setup, this should be a valuable tool for the advanced physics laboratory class, as well as for students wishing independent study projects. The theory involves some advanced quantum mechanics, but students should be able to learn enough to benefit greatly from hands-on experiments.