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Center for Emergent Materials
The Ohio State University
http://cem.osu.edu
New materials for the spintronic toolbox
Highly ordered Sr2CrReO6 films shed light on the role of spin-orbit coupling
The field of “spintronics” has the potential to deliver electronic
devices that are both faster and consume less power than the
current devices. To realize this potential materials where the
spins of the mobile electrons are spin polarized are needed.
The double perovskite Sr2CrReO6 is one such promising
material. Theoretical studies predict that at room temperature it
should be a metal where 85−100% of the mobile electrons have
parallel spins. However, experimental studies of Sr2CrReO6
have been hampered by the inability of researchers to keep Cr
and Re atoms from occasionally switching places in the crystal.
These “mistakes” called antisite defects negatively impact the
magnetic and electrical properties. Researchers at The Ohio
State University have for the first time succeeded in preparing
high quality epitaxial films of Sr2CrReO6 where the Cr and Re
atoms are nearly perfectly ordered. Measurements made on
these films shed new light on the properties of this material. The
effect of spin-orbit coupling, a property associated with
compounds containing heavy elements (in this case Re), is
evident in the magnetic properties.
(a) STEM images of a Sr2CrReO6 (001) film viewed along <110>
direction, showing the high degree of Cr/Re ordering. (b) A lowmagnification TEM image of a Sr2CrReO6 film showing no visible
dislocation defects.
More surprising is the observation that the material is a
semiconductor rather than a metal, something that had not
been anticipated. Not only is the ability to grow highly ordered
double perovskite films a technological breakthrough,
the
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unexpected semiconducting behavior is likely to stimulate new Fengyuan Yang, Adam Hauser, Hamish Fraser, Robert Williams, Manisha
Genc, Jennifer Soliz, & Patrick Woodward
studies to understand the intriguing properties of Sr2CrReO6.
An NSF Materials Research Science and Engineering Center (MRSEC)
Supported under Award Number DMR-0820414