|
Hpc /
K3-xFe5F15DONE Hyp: the site is always the center of a defective (no K) perovskite cube, the perovskite cube in K2Fe5F15. It is always present in all K3-xFe5F15, including K3-δFe5F15. Under the assumption of collinearity his allows to draw conclusions on the magnetic moment variation with x (around a defective site). Check that the perovskite interstitial is compatible with dipolar fields for T<TN and FMuF for T>TN. The FMuF fits below support this view:
Checked against sites where the dipolar field for {$m_\taxt{Fe} = 4.75 \mu_B$} is within {0.5 \le B_d\le 1$ T at all symmetry replicas. None is close to midways between two F ions within 2.8 A. Actually the fit dictates that the muon must be midway between two F ions 2.42 A away, but even if we allow for some relaxation, there is none so near. There are instead many sites at any chosen distance from just one F ion. However the hm fit (single nucleus) is far from acceptable (best {$\chi_r^2=1.2$} on K2 at 160K, where it should be {$0.97\le \chi_r^2\le 1.03$} on that dataset). It is probably necessary to see if the structure relaxes to a muon site with two much closer F than in the regular lattice. In this process developed a mulab fit FMuF with an angle by
pretty useless, for now, the straight fmuf plus a longitudinal decay function fits ok. Looks as if there are two sites, an FMuF and a site far from Fluorines. Look back at dipolar fields. |
||||||||||||||||||||||||
