Combinatorial Synthesis and
Characterization of Magnetic
Alloys
Synthesis
of new alloys
and compounds holds one of the keys to scientific and technological
advances.
This is particularly true in electronics materials, where finding the
materials
that can generate and filter spin polarized electrons is critically
important
for developing the next generation spin polarized electronics,
'spintronics'.
Since the Stone Age, materials have been synthesized and studied one at
a time,
but this 'hit or miss' process is becoming exceedingly difficult owing
to the
complex nature of candidate materials, which often involve particular
arrangements of more than three elements.
We
have developed
techniques to synthesize and characterize complete combinations of an
alloy
system using one or a few substrates. An example is shown below for the
magnetic properties of a ternary system containing Co, Mn, and Ge,
grown
epitaxially on Ge (100) substrate. The result appeared on the cover of
the
April 2002 issue of MRS Bulletin and in a feature
article in the same
issue - "Continuous
phase diagramming of epitaxial films" by Yoo &
Tsui, page 316). From these measurements, ferromagnetic (F) and
antimagnetic
(AF) regions with high transition temperature and high spin
polarization and
paramagnetic (P) regions can be identified for the first time, and the
interplay between structure, magnetism, and transport can be studied
systematically. Fundamental processes that control epitaxial growth and
spin
polarization of these complex systems are being explored.
|