Summary of the research data supporting "Understanding the porosity and its effects on the superconducting properties of YBCO single grains" 
The datasets related to this publication:
Raw_data.xlsx, Raw_data_trapped_field.xlsx,
1_13mm_YBCO_microscope.tif, 2_13mm_YBCO_microscope.tif, 3_13mm_YBCO_microscope.tif, 4_13mm_YBCO_microscope.tif, 5_13mm_YBCO_microscope.tif,
969_16mm_YBCO_microscope.tif, 972_16mm_YBCO_microscope.tif, 982_16mm_YBCO_microscope.tif, 984_16mm_YBCO_microscope.tif, 991_16mm_YBCO_microscope.tif,
F5-1_20mm_YBCO_microscope.tif, F5-2_20mm_YBCO_microscope.tif, F5-4_20mm_YBCO_microscope.tif, F8-2_20mm_YBCO_microscope.tif, F12-2_20mm_YBCO_microscope.tif,
1362_25mm_YBCO_microscope.tif, 1373_25mm_YBCO_microscope.tif, 1374_25mm_YBCO_microscope.tif, 1375_25mm_YBCO_microscope.tif, 
1367_30mm_YBCO_microscope.tif, 1376_30mm_YBCO_microscope.tif,
1377_40mm_YBCO_microscope.tif
can be opened in Microsoft Excel (.xlsx), Notepad (.txt), and image viewers (.tif)
The supporting information is published at: https://doi.org/10.17863/CAM.87761

The .tif images contain the microscope images taken by the OLYMPUS BX51M tracking microscope. Each image was analysed using ImageJ in the following sequence:
1. The image was converted to an 8-bit image
2. The scale was set to:
1: length: 1 pix= 8.64 µm; height: 1 pix = 8.27 µm
2: length: 1 pix= 8.64 µm; height: 1 pix = 8.17 µm
3: length: 1 pix= 8.64 µm; height: 1 pix = 8.31 µm
4: length: 1 pix= 8.64 µm; height: 1 pix = 8.05 µm
5: length: 1 pix= 8.64 µm; height: 1 pix = 7.81 µm
16.0 mm samples:
969: length: 1 pix= 9.83 µm; height: 1 pix = 8.78 µm
972: length: 1 pix= 9.83 µm; height: 1 pix = 8.76 µm
982: length: 1 pix= 9.83 µm; height: 1 pix = 8.30 µm
984: length: 1 pix= 9.83 µm; height: 1 pix = 9.27 µm
991: length: 1 pix= 8.64 µm; height: 1 pix = 7.84 µm
20.8 mm samples:
F5-1: length: 1 pix= 11.40 µm; height: 1 pix = 12.25 µm
F5-2: length: 1 pix= 11.40 µm; height: 1 pix = 12.15 µm
F5-4: length: 1 pix= 11.40 µm; height: 1 pix = 12.40 µm
F8-2: length: 1 pix= 11.40 µm; height: 1 pix = 12.18 µm
F12-2: length: 1 pix= 11.40 µm; height: 1 pix = 11.97 µm
24.8 mm samples:
1362: length: 1 pix= 14.20 µm; height: 1 pix = 15.32 µm
1373: length: 1 pix= 13.26 µm; height: 1 pix = 14.27 µm
1374: length: 1 pix= 14.20 µm; height: 1 pix = 15.29 µm
1375: length: 1 pix= 14.20 µm; height: 1 pix = 15.07 µm
30.7 mm samples:
1367: length: 1 pix= 16.99 µm; height: 1 pix = 18.30 µm
1376: length: 1 pix= 16.06 µm; height: 1 pix = 17.22 µm
41.8 mm samples:
1377: length: 1 pix= 21.64 µm; height: 1 pix = 23.35 µm
3. The threshold was set individually for each image. So that all pores are marked.
4. Particles were analysed with analyze>analyze particles
Settings:
Particle size: 0.001-1.00 mm
Circularity: 0.45-1.00
5. Additional pores were selected, and non-pores were deselected manually
6. The selected pores were sent to the ROI Manager: Image>Overlay>To ROI Manager
7. The colour of the Pores (= overlay) was set to black, and they were introduced in a white image of the same size as the original .tif image 
8. The overlay was flattened, the image converted to 8-bit, and the threshold set to overlap with the pores.
9. The pore sizes and pore count were determined with analyze>analyze particles (green pores in the .tif files)
Settings: 
Particle size: 0-infinity
Circularity: 0-1.00
10. Pores which could not be determined with the analyze particle tool were counted manually (red dots in the .tif files)
11. Pores close to each other were sometimes counted as one by the analyze particles tool of ImageJ. Therefore, they were also counted manually (blue dots in the .tif files)

Raw_data.xlsx: Contains raw data about all 22 investigated bulk samples:
Sample number: Reference number for each sample
Diameter and height: Diameter and height of the cylindrical samples in millimetres. Both were measured with a digital slide gauge.
Area: Area of the cross-section determined from the microscope images (.tif files) in square millimetres determined by ImageJ.
Pore count: Number of pores from each sample determined by ImageJ.
Average pore size: Average pore size for each sample in square millimetres determined by ImageJ.
Porosity: Porosity of each sample in %. Calculation: Porosity = (Pore count*Average pore size)/Area
Trapped field top: Trapped field measured on the top surface in Tesla.
Trapped field bottom: Trapped field measured on the bottom surface of each sample in Tesla.
=> The trapped field was measured with a Hirst GM05 Gaussmeter with the active area 0.5 mm above the sample. 
As the bulk samples were measured in liquid nitrogen, the Gaussmeter was calibrated, and the actual trapped field can be calculated with the equation: Btrapped = Btrapped,measured*0.8685+0.0298.
Jc top: Average critical current density calculated from the trapped field measured on the top surface of the sample. The data needs to be multiplied by 10^4 and is in Ampere per square centimetre
Jc bottom: Average critical current density calculated from the trapped field measured on the bottom surface of the sample. The data needs to be multiplied by 10^4 and is in Ampere per square centimetre
=> The formula for the calculation of the average Jc can be found in the paper (Equation 4)
Pore sizes: The size of each pore shown in green on the .tif images in µm^2. The pore size distribution in Figure 6 was plotted from this data. The pore size in µm was calculated assuming that the pores are spherical.
13.6 mm: Pore sizes in samples 1, 2, 3, 4, and 5.
16.0 mm: Pore sizes in samples 969, 972, 982, 984. and 991.
20.8 mm: Pore sizes in samples F5-1, F5-2, F5-4, F8-2, and F12-2.
24.8 mm: Pore sizes in samples 1362, 1373, 1374, and 1375.
30.7 mm: Pore sizes in samples 1367 and 1376.
41.8 mm: Pore sizes in sample 1377.

Raw_data_trapped_field.xlsx contains raw data of the trapped field for samples 2 (13.6 mm), 969 (16.0 mm), F5-2 (20.8 mm), 1362 (24.8 mm), 1367 (30.7 mm) and 1377 (41.8 mm):
Field: This is the field measured in Tesla by an array of 18 rotating hall probes 1.5 mm above the sample. The Bulk Superconductivity Group Cambridge built this measurement device.
x and y: Are the x and y positions of the hall sensors in mm distance from the centre of the array.