Abstract
The wave-vector and doping dependences of the magnetic energy, iron moment, and effective exchange interactions in and are studied by self-consistent LSDA calculations for co-planar spin spirals. For the undoped compounds , the minimum of the calculated total energy, , is for corresponding to stripe antiferromagnetic order. Already at low levels of electron doping , this minimum becomes flat in and for , it shifts to an incommensurate . In , stripe order remains stable for hole doping up to . These results are explained in terms of the band structure. The magnetic interactions cannot be accurately described by a simple classical Heisenberg model and the effective exchange interactions fitted to depend strongly on doping. The doping dependence of the curves is compared with that of the noninteracting magnetic susceptibility for which similar trends are found.
1 More- Received 24 October 2008
DOI:https://doi.org/10.1103/PhysRevB.79.144421
©2009 American Physical Society
Synopsis
Magnetic order is no match for the lattice
Published 27 April 2009
Density-functional calculations provide a comprehensive picture of how magnetic order evolves with doping in two iron pnictide compounds.
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