We report a study of oxygen isotope effects on the low-temperature specific heat, magnetization, and resistivity of La1-xCaxMnO3 and (La1-yPry)0.67Ca0.33 MnO3. For metallic compositions of La1-xCaxMnO3 and for charge-ordered La0.5Ca0.5MnO3 no change in the low-temperature specific heat has been detected with 16O-18O exchange, while compounds of (La1-yPry)0.67Ca0.33 MnO3 (0.4<y<0.6) show a significant change in low-temperature properties. The low-temperature specific heat indicates the presence of a charge-ordered phase even in compositions of (La1-yPry)0.67Ca0.33 MnO3 which are metallic at low temperatures. We suggest that the changes induced by the oxygen isotope exchange are caused by an increase of the charge-ordered phase in 18O samples.
|Original language||English (US)|
|Number of pages||9|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Mar 1 2002|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics