Low-field Magnetoresistance, Specific Heat and Magnetocaloric Effect in Sr Substituted Pr0.7Ca0.3MnO3

Dogra A, Rayaprol S, Bhattacharya S, Eul M, Hermes W, Pöttgen R

Zusammenfassung

We investigate the effect of ionic size variation on the electrical and thermodynamic properties in a series of Pr0.7Ca0.3-x Sr x MnO3 (PCSMO) samples. The increase in Sr content results in an increase of the unit cell volume, as a bigger Sr2+ ion replaces the smaller Ca2+ ions. Resistivity measurements show that the increase in the Sr content also results in the induction of a metal-insulator transition(T MI), which increases with increasing Sr content. The activation energy(E a), calculated from the resistivity data, decreases with increasing Sr content confirming the metallic character. The effect of the magnetic field on resistivity and specific heat has also been studied.