  We report spin valve behavior in an organic nanowire consisting of three
layers - cobalt, Alq3 and nickel - all nominally 50 nm in diameter. Based on
the data, we conclude that the dominant spin relaxation mechanism in Alq3 is
the Elliott-Yafet mode. Despite the very short momentum relaxation time, the
spin relaxation time is found to be very long - at least a few milliseconds -
and relatively temperature independent up to 100 K. To our knowledge, this is
the first demonstration of an organic nanoscale spin valve, as well as the
first determination of the primary spin relaxation mechanism in organics. The
unusually long spin relaxation time makes these materials ideal platforms for
some areas of spintronics.

Mesoscale and Nanoscale Physics