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Functional Oxides Can Be Switched Between Distinct Structures and Properties via Electrochemical Bias

 

Schematic
of
the BM-SCO and P-SCO thin film on YSZ substrate

 

Functional oxides with perovskite
structure (ABO
3) are
an attractive group of materials for energy and information applications. They
are the key enabler for several important technologies, including solid oxide
fuel cells, thermal-chemical fuel production as well as novel memory devices
such as red-ox based
memristive
systems.
Importantly,
their
physical
and
chemical
properties
can be tuned by controlling the oxygen content in them, conventionally done by
varying the environment temperature and pressure.


MIT MRSEC researchers have
demonstrated that an externally applied electrochemical bias can tremendously
alter the oxygen content, structure and properties of a perovskite,
SrCoOx
(SCO).
SrCoO
x can be flipped reversibly between
two related phases by the bias applied – the perovskite SrCoO
3-δ and
a more open-structured
brownmillerite
SrCoO
2.5. The electrical conductivity,
oxide ion conductivity, magnetism
and
thermal conductivity of these two phases are distinct, and now feasibly
controllable via an external bias.


These results
pave
the way to the
use of electrical bias to control
the oxygen content and to obtain
fast and easily-accessible
switching between different phases
and distinct
properties
of
functional
oxides
important for energy and information technologies.