Phase separation in polycrystalline Pr0.5Sr0.5ÀxCaxMnO3

D. NIEBIESKIKWIAT; D.M. SANCHEZ; A. CANEIRO; B. ALASCIO

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2001 vol. 63 p. 212402 - 212406

1098-0121

In this work we present electrical resistivity and magnetization (M) data as a function of temperature T andmagnetic field H of polycrystalline Pr0.5Sr0.52xCaxMnO3 (x50.1 and 0.2!. Within a large T range we haveobserved the coexistence of the ferromagnetic ~FM! and charge-ordered antiferromagnetic phases. From thespontaneous magnetization in the M(H) curves we obtained the fraction of the FM phase XFM . We found thatXFM is ;20% at low T, and increases by increasing both T and H. Through a simple free-energy model drivenby random disorder, we reproduce the T and H evolution of the phase-separation phenomena. We also showthat a low-energy difference between the competing states is responsible for the dramatic effects that thedisorder has on the physical properties.