highly oriented pyrolytic graphite

initialism: HOPG
https://doi.org/10.1351/goldbook.H02823
Highly oriented pyrolytic graphite (HOPG) is a pyrolytic graphite with an angular spread of the c-axes of the crystallites of less than 1 degree.
Note: Commercial HOPG is usually produced by stress annealing at approximately \(3300\ \rm{K}\).
Source:
PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 495 [Terms] [Paper]