Abstract
We report the results of a neutron diffraction study, carried out on both single crystalline and polycrystalline samples of and polycrystalline . On cooling, at approximately 120 K, the system undergoes a magnetoelastic transition from a high-temperature monoclinic-paramagnetic to a low-temperature orthorhombic-ferromagnetic structure. Between 120 K and 75 K, the magnetic structure has a net ferromagnetic component along the axis direction. The moments are slightly canted with respect to the axis, while the components along the and axes are ordered antiferromagnetically. A second magnetic transition occurs at approximately 75 K. Below this temperature, the magnetic structure consists of ferromagnetically aligned and projections of the magnetic moments and an antiferromagnetic arrangement of the moment components. Magnetic structures of are nearly identical to those of .
- Received 5 March 2005
DOI:https://doi.org/10.1103/PhysRevB.72.104431
©2005 American Physical Society