Stability, bistability and instability of amorphous ZrO2 resistive memory devices
P Parreira, G W Paterson, S McVitie and D A MacLaren
SUPA, School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, UK

E-mail: pedromiguel.raimundoparreira@glasgow.ac.uk and dmaclaren@physics.org


Raw data TEM files are in Gatan's Digital Micrograph file format (details at the time of writing are advertised at: http://www.gatan.com/products/tem-analysis/gatan-microscopy-suite-software). 
Data was acquired using a JEOL ARMcFEG instrument operated at 200kV, using a Gatan Quantum electron spectrometer for EELS measurements (see manuscript for details). Spectrum imaging is performed by first collecting a dark field 'survey image' then acquiring data within a sub-region indicated within the survey. For the datasets used here, two EELS spectra (low-loss and core loss) an EDS spectrum and dark field images from two detectors ('Gatan DF' and 'Gatan HAADF') are recorded; the file names generally indicate the nature of each subset of the data. See references 23 & 24 for descriptions of the spectrum imaging technique.
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Figure 1a is a DF survey image highlighting where the normalised composition distrbution in figure 1b is obtained from. Fig 1a raw data: "Fig1 Survey Image(active).dm3"

Fig 1b raw data: "Fig1_EELS Spectrum Image (high-loss).dm3", "Fig1_EELS Spectrum Image (low-loss).dm3" and "Fig1_EDS Spectrum Image.dm3" were processed using standard routines within Digital micrograph, starting with the use of the low-loss signal to correct for apparent energy drifts within the core loss data. See text and references 23 & 24 of the main text for details.

Figures 1c, 1d, 1e and 1f derive from processing of the spectrum image collected within region 2 of figure 1a. The spectrum image files are all named starting with 'Fig1c'. See the above references and the main text for typical processing details. Figure 1c shows the spatial distribution of the chemical shift highlighted in figure 1d. The data of "Fig1c_EELS Spectrum Image (high-loss).dm3" is processed, then the region of the Ti L edge that corresponds to the chemical shift is selected using the spectrum map tools available within DM. Figure 1d shows details of the selected spectra.

Figure 1e shows the spatial distribution of the O/Zr obtained by dividing the O and Zr spectrum maps, again derived after processing of "Fig1c_EELS Spectrum Image (high-loss).dm3"
Figure 1f shows the differences in the O K edge extracted from different regions, derived from the same spectrum image.
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Figures 2-4 obtained by plotting the I-V or logI-logV directly from the raw data.
Fig 2a raw data: "Fig2a_1.csv" and "Fig2a_2.csv"
Fig 2b raw data: "Fig2b.csv"

Fig 3a and 3b: obtained by plotting abs(logI)-abs(logV) of the data presented in Fig2, and by fitting linear trends as indicated.

Fig 4 shows sub variability observed for the two main switching modes.  The raw data are on sheet 3 of "Fig4.xlsx"