The low-temperature phase separation in Pr0.5Ca0.5CoO3

Role ofA-site cations in the metal-insulator transition inPr0.5Ca0.5CoOBarón-González1, Frontera2, García-Muñoz3 et al. 2010Phys. Rev. B385600View full textAdd to dashboardCite

“…As reported in previous works, 14,18,19 there is an important contraction of V on cooling across the transition. Spin-state transitions of Co ions are in fact accompanied by perceptible cell volume changes but these changes are driven by changes in Co size ͑deduced from the mean Co-O bond distance͒ induced by the new spin state.…”

“…[14][15][16][17][18][19] Besides, our measurements show that above 100 K, an applied field of 9 T scarcely affects the resistivity and, in fact, slightly enlarges with the field. This demonstrates that the mobility of itinerant electrons does not depend on the magnetic arrangement of the core spins ͑t 2g 5 ͒.…”

“…[14][15][16][17][18][19][20][21][22] This compound presents, on cooling a sudden increase in the resistivity, usually described as a metal to insulator transition ͑MIT͒. It is accompanied by an anisotropic cell anomaly and a sudden large cell volume contraction.…”

Valence transition in (Pr,Ca)CoO3cobaltites: Charge migration at the metal-insulator transition

“…2 across the transition. [20][21][22] The change θ 1 is the main cause of opposite spatial shifts of Pr and O1 atoms within the a-c plane: u x = 0.0079, u z = −0.0023 and |s| = 0.044Å for Pr, and u x = −0.0044, u z = 0.0097, and |s| = 0.0567Å for O1, where u i are the relative and |s| the total displacements.…”

“…Moreover, a (Pr,Ca)-O bond contraction has been observed across T MI . [20][21][22] In this work we present x-ray absorption measurements at the Pr 20 Final sintering of the samples was performed under high oxygen pressure (p O 2 = 200 bars) to assure optimal oxygen content. Samples were well crystallized and free from impurities as revealed by x-ray and neutron diffraction.…”