Lattice and magnetic instabilities in CaFe2As2: A single crystal neutron diffraction study

Abstract

Neutron diffraction measurements of a high quality single crystal of CaFe2As2 are reported. A sharp transition was observed between the high temperature tetragonal and low temperature orthorhombic structures at TS = 172.5K (on cooling) and 173.5K (on warming). Coincident with the structural transition we observe a rapid, but continuous, ordering of the Fe moments, in a commensurate antiferromagnetic structure is observed, with a saturated moment of 0.80(5)muB/Fe directed along the orthorhombic a-axis. The hysteresis of the structural transition is 1K between cooling and warming and is consistent with previous thermodynamic, transport and single crystal x-ray studies. The temperature onset of magnetic ordering shifts rigidly with the structural transition providing the clearest evidence to date of the coupling between the structural and magnetic transitions in this material and the broader class of iron arsenides.

submitted to PRB

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Cited by in corpus (3)

• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Commensurate Itinerant Antiferromagnetism in BaFe2As2: 75As-NMR Studies on a Self-Flux Grown Single Crystal
• Strong coupling between magnetic and structural order parameters in SrFe2As2