High-pressure effects on the resistivity and ferromagnetic transition of ceramic manganite Ca1-xYxMnO3

The effect of hydrostatic pressure up to 1 GPa on the electrical resistivity and on the ferromagnetic transition temperature T-c is systematically investigated for the electron-doped manganite Ca1-xYxMnO3 for low electron density (x less than or equal to 0.2). We find that T-c is nearly constant for pressures roughly below 0.5 GPa and shows a linear increase for higher pressures, with a slope varying with the x content. Our results are discussed considering the enhancement of the electronic bandwidth with pressure related to double exchange and polaronic contributions, The unusual pressure dependence of T-c obtained can also be related to a competition scenario between double exchange mechanism and antiferromagnetic superexchange interactions proposed for electron-doped manganites. (C) 2001 Elsevier Science B.V. All rights reserved.