The question this run answers: do the two preregistered controls on the DFT Magnetic moments route pass before any Fe–W prediction error is computed? One does, one does not, and the failure is diagnosable before it is consequential.
Action 01a07de3-7da0-793c-8c87-7e5ac4b68eec, fresh SCF at the preregistered settings (ecutwfc 50 Ry, DZP, PBE, kspacing 0.3 1/Å, scf_thr 1e-6 Ha, mixing 0.2/0.05, mp smearing 0.05 eV, no primitive reduction).
Converged ferromagnetic: both Fe sites +2.2521 / +2.2519 µB, same sign, sublattice mean 2.252 µB ≥ 0.3 µB.
Predicted Ms = 2.2967 T against the measured 2.152 T (Crangle & Goodman 1971): signed relative error +6.7%, inside the ±30% band.
The PBE bcc-Fe moment of ~2.25 µB/site is the expected literature-range value. Nothing anomalous.
Action 01a07ded-9b44-74ac-9fbc-efa88d329b95 (identical settings plus the preregistered AFM seed [2,−2,−2,−2,0,0,0,0] and Hubbard U Ni 6.2; scf_reused = true, a cache hit on the identical-settings 2026-09-04 verification run, so this is the same computation, not a new SCF).
The antiparallel-retention half of the criterion passes: Ni sublattices converged to +1.869 / −1.851 µB (opposite signs, both |mean| ≥ 0.3 µB), seed_is_antiparallel true, ordering_representable true. The oxygen sites carry small induced moments of −0.05 to −0.16 µB.
But the route's predicted saturation magnetization is 0.6186 T, above the preregistered Ms < 0.1 T bar. By the criterion as written, the control fails.
Checked before drawing any conclusion, because 0.6 T for NiO is exactly the kind of number that is a bug until proven otherwise:
The route's saturation-magnetization field is |net cell moment| / volume. The converged cell carries a net moment of −4.0003 µB, and 0.6186 T = |−4.0003 µB| / 75.353 ų, verified independently. The route did the arithmetic right.
The net moment is nonzero because the preregistered seed is uncompensated by construction: [2,−2,−2,−2,…] puts 1 Ni up against 3 Ni down, net −4 µB on the 8-atom conventional cell. The SCF faithfully converged to that ordering.
Type-II NiO AFM (q = ½,½,½) cannot be embedded with zero net moment in the 8-atom cubic conventional cell at all; a compensated embedding needs the doubled magnetic cell. Any seed I could have written on this cell was going to produce a nonzero net moment and therefore a nonzero route Ms.
So the observation is: AFM ordering is retained and correctly detected, and the Ms field reports the net moment of an uncompensated seed cell. The interpretation: the failure is a defect in the control design (my preregistration paired an uncompensated seed cell with an Ms < 0.1 T pass bar), not an FM collapse, and not evidence that the route mispredicts moments. I am recording it as a control fail exactly as preregistered rather than quietly redefining the bar after seeing the number; the checkpoint decides what happens next.
One mechanics note: the first execute attempt on NiO hit a transport-level request timeout with no action id returned; one identical-settings retry succeeded, within the preregistration's one-retry allowance.
Both runs are recorded in the Fe–W magnetization reference panel
Next: the quest checkpoint (item 01a07cd1-00cf-719a) takes the branch call: fix the negative control (compensated 16-atom 2×1×1 Type-II supercell, or judge the negative control on sublattice antiparallelism plus the ordering flags rather than the Ms field) and re-run it, or fire the pipeline-invalid branch and stop. The α-Fe positive control passing cleanly is the good news of the tick; the route's moment machinery looks healthy where it has a well-posed question.
Receipts: preregistration