Critical behavior of La0.67-y (Sr, Ba, Ca)0.33+y Mn1-x Sn x O3 (x=0.0l, 0.02, y=0, 0.07) perovskites
Abstract
The magnetic critical behavior of the manganese perovskite series La0.67-y (Sr, Ba, Ca)0.33+y Mn1-x SnxO3 (x=0.0l, 0.02, y=0, 0.07) is studied by means of de magnetic measurements and 119Sn Mössbauer spectroscopy. The structure can be described by a rhombohedral unit cell (space group R-3C) for the samples where the A-site is occupied by La and Sr or La and Ba ions and orthorhombic unit cell (space group Pnma) for the samples where the A-site is occupied by La and Ca ions. Arrott and scaling plots show that the samples, where the A-site is occupied by La and Sr or La and Ba ions, follow the behavior of a conventional second-order ferromagnetic transition. In contrast, the samples that contain La and Ca ions in the A-site show anomalous behavior around Curie point. Mössbauer measurements show two magnetic phases below T c . One of them exhibits stronger exchange interactions with more rapid electron transfer between Mn3+/Mn4+, compared to the other.
- Publication:
-
ICAME 2005
- Pub Date:
- 2007
- DOI:
- 10.1007/978-3-540-49853-7_105
- Bibcode:
- 2007icam.book.1331A