Transport properties of electron rich Sm 0.2Ca 0.8Mn 1-xRu xO 3(x=0; 0.04) were measured under hydrostatic pressures up to 1 GPa and applied magnetic fields up to 1.5 T at the temperature interval 77<T<300 K including critical points of these manganites. The 4% Ru doping in Mn site converts low temperature robust orbitally ordered (OO) antiferromagnetic (AF) phase observed in the undoped compound to a two-phase [coexisting ferromagnetic metallic (FMM) and OO/AF phases] state. As a result of the appearance of the phase separated state, colossal magnetoresistance and slow relaxation of resistivity with logarithmic time dependence that are enhanced by pressure, are observed in Sm 0.2Ca 0.8Mn 0.96Ru 0.04O 3. In contrast, negative magnetoresistance, originated from some minute FM interaction that was observed in Sm 0.2Ca 0.8MnO 3, is depressed and practically vanished by external pressure. Except for this, the relaxation of resistivity is also absent in Sm 0.2Ca 0.8MnO 3.
ASJC Scopus subject areas
- Physics and Astronomy (all)