The magnetic structure of the series (formula presented) for y from 0.5 to 1.0 has been studied by neutron powder diffraction in the temperature range from 10 to 293 K and in external magnetic fields up to 4 T. The phase diagram has a border region of concentrations (formula presented) separating the homogeneous ferromagnetic (FM) metallic and canted antiferromagnetic (AFM) insulating states. In this region the low-temperature magnetic state is macroscopically (formula presented) separated into AFM and FM phases. The FM phase has a small noncollinearity, presumably due to interfaces to the AFM phase. The macroscopical clusters can be induced by disorder on the carrier’s hopping amplitude caused by natural dispersion of the A cation radius near the metal-insulator transition around (formula presented) For the concentrations (formula presented) the long-range ordered magnetic state is homogeneous with a canted AFM structure. The total long-range ordered magnetic moment of the Mn ion shows a steplike decrease from (formula presented) to (formula presented) as a function of Pr concentration at the transition to a homogeneous canted antiferromagnetic (CAF) state. The spatial inhomogeneities can still be present for (formula presented) according to the reduced (formula presented) value, but the Mn spins between the homogeneously CAF-ordered moments have to be either short-range ordered or paramagnetic. In addition, a ferromagnetic contribution of the Pr moments parallel to the ferromagnetic component of Mn moments is found for (formula presented) The moment of Pr scales with the ferromagnetic Mn moment rather than with the Pr concentration and thus presumably induced by Mn.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2001|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics