Spin dependent electron transfer across metal/molecule interfaces

COLL 455

Gregory J. Szulczewski, gjs@bama.ua.edu, Department of Chemistry, The University of Alabama, 250 Hackberry Lane, Box 870336, Tuscaloosa, AL 35487, Weihao Xu, xu015@bama.ua.edu, Department of Chemistry, University of Alabama, Tuscaloosa, AL, Patrick LeClair, pleclair@mint.ua.edu, Department of Physics, University of Alabama, Tuscaloosa, AL 35487, and Arun Gupta, agupta@mint.ua.edu, MINT Center, University of Alabama, Tuscaloosa, AL 35487.
In this talk we will present experimental results that demonstrate efficient transport of spin-polarized electrons across molecular layers. The evidence for spin-polarized interfacial transfer comes from two sets of experiments. In the first set of experiments we use the ferromagnetic oxide, La0.67Sr0.33MnO3,as a source of spin-polarized electrons to tunnel across molecular barriers into Co electrodes. These devices exhibit a negative tunneling magnetoresistance (TMR) of about 25% at cryogenic temperatures. The TMR decreases with both increasing bias voltage and temperature. In the second set of experiments we directly measure the spin-polarization of electrons tunneling from Co electrodes across molecular barriers into a superconducting Al film that serves as a spin detector. Robust theoretical models will be presented to describe both sets of data.
 

Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to Nanomaterials
8:40 AM-12:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 226, Oral

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008