We have peformed neutron diffraction measurements on melt-grown polycrystalline samples of Nd1-xSrxMnO3(0.49 < x < 0.75). A systematic transformation of the crystalline and magnetic structures of this system was observed. This can be consistently explained by the change of the character of the Mn egorbitals. When increasing X, the Nd1-xSrxMnO3system exhibits an evolution from a metallic ferromagnetic state, to a metallic A-type antiferromagnetic (AFM), and then to an insulating C-type AFM state. The CE-type charge-ordered AFM state was observed only in the vicinity of x = 1/2 and it coexists with the A-type AFM state for x ≳ 1/2, indicating that the energy difference between these two states is very small. We also found that the MnO6octahedra are apically compressed in the CE-type and A-type AFM states due to the d(3x2-r2)/d(3y2-r2) or d(x2-y2) orbital ordering, whereas they are apically elongated by the rod-type d(3z2-r2) orbital ordering in the C-type AFM state. Finally, a selective broadening of Bragg peaks was observed in the C-type AFM phase and its x dependence strongly suggests the onset of charge ordering for either x=4/5 or x=3/4.
|Number of pages||12|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics