We report anomalous post-annealing effects of La0.8Ca0.2MnO3 under O2 and Ar atmospheres. We have found that the critical temperature (TC) of the as-prepared sample increases after Ar-annealing and decreases upon O2 annealing. The temperature-dependent magnetization data of the as-prepared compound agree well with the sum of those of the O2- and Ar-annealed samples. Colossal magnetoresistance (CMR) below 60 K that reaches to almost 100% is observed in the O2-annealed sample. These unusual results are discussed in terms of global homogenization over the sample and magnetic inhomogeneity induced by the Mn deficiency.
- A. Magnetically orderd materials
- A. Perovskite Manganites
- D. Colossal magnetoresistance
ASJC Scopus subject areas
- Condensed Matter Physics
- Materials Chemistry