Abstract
Polycrystalline samples of n = 1 Ruddlesden-Popper manganites Nd1-xCa1+xMnO4 (0.55 ≦ x ≦ 1.00) were synthesized by a solid-state reaction. X-ray diffraction (XRD) and electron diffraction (ED) measurements confirmed that the fundamental crystal structure at room temperature consists of three distorted K2NiF4-types: orthorhombic Bmab (64) phase in 0.55 ≦ x < 0.73, orthorhombic Acam (64) phase in 0.73 ≦ x < 0.85 and tetragonal I41/acd (142) phase in 0.85 ≦ x ≦ 1.00. Furthermore, in a whole range of 0.55 ≦ x ≦ 0.75, low-temperature magnetic and ED measurements revealed charge-orbital ordering (COO) states, which are accompanied by suppression of magnetization and structural modulations with q = (1 - x)a*. The COO transition temperatures are high with a maximum of ∼330 K at x = 0.67, and then higher than those in non-distorted n = 1 Ruddlesden-Popper manganites. The observations suggest that COO states are much stabilized by the distortion in the fundamental structures.
Original language | English |
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Pages (from-to) | 247-252 |
Number of pages | 6 |
Journal | Journal of Alloys and Compounds |
Volume | 453 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 2008 Apr 3 |
Keywords
- Crystal structure and symmetry
- Electronic states (localized)
- Scanning and transmission electron microscopy
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry