کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1596850 | 1002858 | 2006 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Highly cation-deficient manganese perovskite, La1−xMn1−yO3 with x=y Highly cation-deficient manganese perovskite, La1−xMn1−yO3 with x=y](/preview/png/1596850.png)
Oxidative (δ>0) nonstoichiometry in the perovskite ‘LaMnO3+δ’ has been known to be manifested not with O interstitials but rather with cation vacancies of equal amounts at the two cation sites, La and Mn, i.e. La1−xMn1−yO3 with x=y. Here, we report the fabrication of samples with record-high cation-vacancy concentrations (x>0.12 or δ>0.4) by means of a variety of high-pressure oxygenation techniques. Linear (negative) dependence of the cell volume on x was observed within the whole x range investigated, down to 56.9 Å3 (per formula unit) for a sample oxygenated at 5 GPa and 1100 °C using Ag2O2 as an excess oxygen source. With increasing degree of cation deficiency in La1−xMn1−xO3, the ferromagnetic transition temperature was found to follow a bell shape with respect to x exhibiting a maximum of ∼250 K about x≈0.1. For moderately oxygenated samples large magnetoresistance effect was evidenced.
Journal: Solid State Communications - Volume 137, Issue 10, March 2006, Pages 522–527