“…Non-superconducting secondary phases (as well as the broader spectrum of microstructural defects) provide a flux pinning mechanism whereby the magnetic flux quanta are pinned in-place, inhibiting flux movement (Jung et al, 1990;Murakami et al, 1991Murakami et al, , 1994. As a result, a significant amount of effort has been spent testing different pinning methodologies to mitigate flux creep: such as crystallographic defects (Sauerzopf, 1998;Wang et al, 2008), secondary phases (Murakami et al, 1991;Lee et al, 1992;Cantoni & Nissen, 1993;Jiao et al, 2010), or doping (Clausen et al, 1996;Goyal et al, 2005;Ichinose et al, 2008;Mele et al, 2009;Ko et al, 2011;Horide et al, 2013;Matsumoto et al, 2014;Miura et al, 2015). Weak links arise from depletion of the hole concentration at larger misorientation grain boundaries, resulting from oxygen variation or arrangement (Vargas et al, 1997;Babcock, 1999).…”