| The normal state magnetisation of iron pnctides exhibits a universal increase upon heating. The slope and the absolute value of the susceptibility per FeAs-layer at elevated temperatures are independent on doping, irrespectively whether long range antiferromagnetic order, the non-magnetic superconducting ground state are a mixed ground state appears. Our data on LaFeAsOF, LiFeAs, NaFeAs, Ba- and Ca122 etc. single crystals imply the generic nature of this feature. |
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