A preparation method for magnetic tunnel junctions with single crystal GaAs
(001) barriers is demonstrated. The method is based on an epoxy bond and st
op etch technique and does not require epitaxial growth of a semiconductor
on top of a metal. Stable GaAs tunnel barriers down to 6 nm in thickness we
re prepared. The I-V measurements show a pronounced nonlinearity. Their var
iation with temperature depends strongly on the barrier thickness which is
weak for the 6 nm barriers, a clear indication for quantum mechanical tunne
ling as the dominant transport channel. (C) 2001 American Institute of Phys
ics.