(a) Cross-sectional TEM bright field image of SNO film of ∼18 nm thickness deposited on LAO. (b) HRTEM image of substrate/film interface. Inset: FFT patterns taken from both areas indicate oriented crystal structures.
(a) 2θ-θ XRD scan of (002) pseudocubic reflections of LAO and SNO, verifying deposition of SNO phase. (b) Resistivity versus temperature of LAO/SNO. Reversible MIT observed at 405 K, negligible hysteresis between heating and cooling curves.
(a) Two-terminal resistance versus temperature of LAO/SNO for device with W/L = 300/700 μm/μm. MIT observed at 380 K. (b) Solid black line: Room temperature I-V measurement from same device as measured in (a). Dashed blue line: dc resistance V/I computed from I-V measurement. Upturn in resistance above V c ≈ 22 V is evidence of electrically driven MIT. Inset: V/I versus V for device with W/L = 340/20 μm/μm showing transition at lower voltage.
(a) Static resistance V/I versus applied power V·I (dashed red line, measurement at 300 K) overlaid with R-T curve (solid black line) from same device on same ordinate scale. Line shapes and resistance values are in good agreement. Inset: (blue circles) Mapping of temperature to power according to resistance values and line shapes of R-P and R-T curves. Solid green line: Modeling of T-P map by Joule heating as in Eq. (3). (b) Static resistance versus applied power at heating stage temperatures from 300 to 400 K. Critical power, at which upturn in resistance occurs, decreases with increasing temperature and is no longer defined above T MIT. Inset: Critical power versus heating stage temperature (black squares) and linear fit to data (red line), verifying linear relationship between applied power and temperature as in Eq. (3).
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