Correlated metal oxides with insulator-metal transitions and their Nano-scale properties
CIC nanoGUNE Seminars
- Speaker
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Amos Sharoni, Bar Ilan University, Ramat Gan (Israel)
- When
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2015/10/15
13:00 - Place
- nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
- Add to calendar
-
iCal
Many transition metal oxides exhibit spectacular Insulator-Metal-transitions
(IMT) the manipulation of which is essential for their application as active
device elements. However, such manipulation is hindered by lack of microscopic
understanding of mechanisms involved in these transitions. The IMT, during
which conductivity can change by many orders of magnitude, is generally first
order, hysteretic and correlated with structural transitions and often
inhomogeneous.
After a general introduction, I will describe a series of experiments done in
VO2, a prototypical IMT material, to characterize the transition and the
resulting importance of inhomogeneity in understanding the microscopic nature
of the IMT. We have performed local transport, Hall, First Order Reversal
Curve (FORC), impedance spectroscopy, and local temperature measurements.
Interestingly, we find that the IMT occurs through a series of avalanches,
with the avalanche exponent indicative of long-range interactions. High
resolution Hall measurements provide interesting information on the
characteristics of inhomogeneity, while FORC and impedance spectroscopy
measurements confirm the presence of ‘filamentary’ transitions starting
prior and continuing across the IMT.
Finally, I will briefly highlight recently developed nano-fabrication methods
that are undamaging of the delicate transition metal oxide properties, crucial
for integration of such materials into novel oxide-electronic devices.
**Host** : Felix Casanova