Dataset for "High Resolution Spatial Mapping of the Electrocaloric Effect in a Multilayer Ceramic Capacitor using Scanning Thermal Microscopy"

These files are the raw data used to generate the data shown in Figure 2 and Figure 4 in O.E. Baxter, A. Kumar, J. M. Gregg & R. G. P. McQuaid J. Phys: Energy 2023.

The Hierarchical Data Format version 5 (HDF5 or .h5) files contain all data recorded by the Oxford Instruments MFP 3D Asylum Atomic force microscope during the measurement scans. These .h5 files can be opened with Python, which is open source. Five data channels are recorded in each file: (1) Raw, (2) Deflection, (3) Temperature, (4) Applied Bias, (5) Z Sensor. Files are named with a convention such that “Fig2_80micronx20micon_100V_rawdata.h5” refers to the 80 micron by 20 micron area investigated in Figure 2 of our paper with 100 V applied to the sample. Similarly, the file “Fig4_2micronx2micron_100V_rawdata.h5” refers to the 2 micron by 2 micron area studied in Figure 4 with 100 V applied to the sample.

A MATLAB script was used to access the raw temperature information, which was then calibrated into real temperature changes through a calibration correction factor. The total time for the scans was recorded, which meant individual measurement times could be assigned to each data point. Peak temperatures associated with electrocaloric heating/cooling (compared to the baseline average temperature) were extracted from each temperature vs time trace. This information was then used to create a colormap of electrocaloric temperature changes. In the case of Fig 4, this approach was expanded to look at temperature changes at different points in time, rather than just the maximum temperature changes.

Article Abstract
Scanning Thermal Microscopy is emerging as a powerful Atomic Force Microscope based platform for mapping dynamic temperature distributions on the nanoscale. To date, however, spatial imaging of temperature changes in electrocaloric materials using this technique has been very limited. We build on the prior works of Kar-Narayan et al. (Appl. Phys. Lett. 102, 032903, 2013) and Shan et al. (Nano Energy, 67, 104203, 2020) to show that Scanning Thermal Microscopy can be used to spatially map electrocaloric temperature changes on microscopic length scales, here demonstrated in a commercially obtained multilayer ceramic capacitor. In our approach, the electrocaloric response is measured at discrete locations with point-to-point separation as small as 125 nm, allowing for reconstruction of spatial maps of heating and cooling, as well as their temporal evolution. This technique offers a means to investigate electrocaloric responses at sub-micron length scales, which cannot easily be accessed by the more commonly used infrared thermal imaging approaches.