Abstract
We present the results of a neutron-powder-diffraction study in which we have examined the magnetic and structural properties of as a function of doping concentration x and temperature. For charge ordering and a Jahn-Teller distortion below 250 K are evident from rapid changes in the lattice parameters and bond lengths as a function of temperature and a transition from a high-temperature orthorhombic to a low-temperature monoclinic structure. For the system orders antiferromagnetically at At low temperature the system has a canted CE structure. As the temperature approaches there is a transition to a collinear magnetic arrangement. For Sr doping of up to the magnetic transition temperature remains almost constant but the magnetic arrangement now has a ferromagnetic component which persists up to For the charge ordering is removed and the lattice parameters show a more normal temperature dependence. The materials are now simple ferromagnets and the ferromagnetic transition temperature increases rapidly with x.
- Received 6 November 1997
DOI:https://doi.org/10.1103/PhysRevB.58.8694
©1998 American Physical Society