Structural Determination of the Charge Ordering Process in Nd0.5Ca0.5Mn1−xCrxO3 Manganites

✍ Scribed by W Schuddinck; G Van Tendeloo; A Barnabe; M Hervieu; B Raveau

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 559 KB
• Volume: 148
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8457

✦ Synopsis

Structural properties of Cr-doped manganites Nd 0.5 Ca 0.5 Mn 1؊x Cr x O 3 with 0.024x40.07 have been studied versus temperature by electron di4raction and high-resolution electron microscopy between 90 and 300 K. All compositions show an incommensurate superstructure over the whole temperature domain, despite the fact that they are ferromagnetic and conductive below 150 K. The q vector (1/2 ؊ )a* decreases with increasing temperature for all compositions x. For a given temperature q also decreases with x. Room-temperature high-resolution electron microscopy images show point defects similar to those observed for other Ln 0.5 Ca 0.5 MnO 3 manganites with Ln ‫؍‬ + +Pr, Nd, Sm, , and they also show intensity variations. Lattice images obtained at low temperature allow a better understanding of the charge ordering process. The low-temperature form of the Cr-doped manganites is not a perfectly doubled cell 1 11 12a p ( (2 ؋ 2a p ؋ a p ( (22 22 2, but defects inducing a tripled cell occur pseudoperiodically.