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Published byAngela Chaddock Modified over 2 years ago

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140K 2K k=? PrMn 7 O 12 Rhombo : magnetic peaks unindexed Bank 1 Bank 2 Bank 4 Bank 3 Bank 5Bank 6

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PrMn 7 O 12 Rhombo at 140K showing quite a few impurity peaks

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PrMn 7 O 12 Monoclinic : obviously, a k=(0 0 0) structure (magnetic on top of nuclear) 2K 150K k=(000) Bank 1 Bank 2 Bank 4 Bank 3 Bank 5Bank 6

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PrMn 7 O 12 Monoclinic at 2K indexed with k=(0 0 0) propagation vector But A-type structure must have k=(0 1 0): structure cannot be A-type Mag: H+k k=(0 1 0) Nuc t=(½ ½ ½) S S’ S S’=S.exp(2i .k.t) S’=-S (S’=S for k=(0 0 0)) A-type

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PrMn 7 O 12 Monoclinic at 2K indexed with k=(0 0 0) propagation vector Prelim solution involving only Mn B-site C-type

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Conclusions Monoc phase : On dataset at RT, and 150K and 2K in cryo (10 times worse statistics because of cryo bckgd) No visible structural transition down to 2K and fit not “exceptional” (R_B>10%) mag structure k=(000) but no final model (check for A-site cation contrib/other models.…) Rhombo phase: only 2K and 140K collected in cryo as for the monoc sample, no visible structural transition down to 2K and relatively bad fits (R_B>10%) more visibly impure, propagation vector(s) indexing magnetic reflections yet unknown

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