Abstract
Neutron and synchrotron resonant x-ray magnetic scattering (RXMS) complemented by heat capacity and resistivity measurements reveal the evolution of the magnetic structures of Fe and Ce sublattices in a CeFeAsO single crystal. The RXMS of magnetic reflections at the Ce edge shows a magnetic transition that is specific to the Ce antiferromagnetic long-range ordering at 4 K with short-range Ce ordering above , whereas neutron diffraction measurements of a few magnetic reflections indicate a transition at 12 K with an unusual order parameter. Detailed order-parameter measurements on several magnetic reflections by neutrons show a weak anomaly at 4 K that we associate with the Ce ordering. The successive transitions at and can also be clearly identified by two anomalies in heat capacity and resistivity measurements. The higher transition temperature at 12 K is mainly ascribed to Fe spin reorientation transition, below which Fe spins rotate uniformly and gradually in the plane. The Fe spin reorientation transition and short-range Ce ordering above reflect the strong Fe-Ce couplings prior to long-range ordering of the Ce. The evolution of the intricate magnetic structures in CeFeAsO going through and is proposed.
4 More- Received 12 July 2013
DOI:https://doi.org/10.1103/PhysRevB.88.174517
©2013 American Physical Society