Influence of YBa 2 HfO 5.5 – ‘derived secondary phase’ on the critical current density and flux-Pinning force of YBa 2 Cu 3 O 7−δ thick films

Analytical electron microscopy study of the composition of BaHfO3 nanoparticles in REBCO films: the influence of rare-earth ionic radii and REBCO composition

“…Besides BMO, barium-based double-perovskite nanoparticles with the stoichiometric formula Ba 2 BB′O 5.5 or Ba 2 BB′′O 6 are also used in REBCO films. 74–79 These double perovskites consist of a trivalent REE on the B site ( e.g. , B = Y 3+ ) and an element with valence four ( e.g.…”

“…Besides BMO, barium-based double-perovskite nanoparticles with the stoichiometric formula Ba 2 BB 0 O 5.5 or Ba 2 BB 00 O 6 are also used in REBCO films. [74][75][76][77][78][79] These double perovskites consist of a trivalent REE on the B site (e.g., B = Y 3+ ) and an element with valence four (e.g., B 0 = Hf 4+ ) or five (e.g., B 00 = Nb 5+ ) on the B 0 or B 00 sites. The case of Ba 2 RE 3+ Hf 4+ O 5.5 is consistent with our findings for REE-substitution for Hf in the perovskite BHO, even though both crystal structures may not be directly comparable.…”

“…Many publications emphasize the high chemical inertness of double perovskites in REBCO. [74][75][76]79,80 Note that the tolerance factor is only a qualitative metric to predict perovskite-phase stability based on ionic radii. The substitution-site probability may be affected by other aspects such as charge compensation, 44,46 exact A/B cation ratio, 42 or oxygen partial pressure p O 2 .…”