We have measured the oxygen isotope effect on the metal-insulator transition and the electrical properties of La0.65Ca0.35MnO3 under hydrostatic pressure up to 1.7 GPa. The conductivity activation energy EA in the insulating phase is a linear function of Tc and coincides for both isotopes 16O and 18O if compared at different pressures but for the same Tc. The pressure and isotope effects can be qualitatively understood in terms of the double exchange model and the adiabatic hopping of Jahn-Teller polarons. Higher order corrections to the Holstein model in the intermediate coupling regime explain the unusually large isotope effect on the relative pressure coefficient of Tc.
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2001|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics