Possible common ground for the metal-insulator phase transition in the rare-earth nickelates RNiO3, R(Eu, Ho, Y)

FERNANDO P. DE LA CRUZ; CINTHIA PIAMONTEZE; NESTOR E. MASSA; HORACIO SALVA; JOSE´ ANTONIO ALONSO; MARIA JESU´S MARTINEZ-LOPE,; MARÝA TERESA CASAIS

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

American Institute of Physics

Lugar: Mellville; Año: 2002 vol. 66 p. 153104 - 153108

0163-1829

We report on the infrared spectra of RNiO3 (R5Eu, Ho, Y!. They provide evidence of phonon and insulating gap behavior and point to the monoclinic distortion at the metal-insulator ~MI! transition as a feature for all RNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) in all RNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) in gap behavior and point to the monoclinic distortion at the metal-insulator ~MI! transition as a feature for all RNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) in all RNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) in RNiO3 (R5Eu, Ho, Y!. They provide evidence of phonon and insulating gap behavior and point to the monoclinic distortion at the metal-insulator ~MI! transition as a feature for all RNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) in all RNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) in ~MI! transition as a feature for all RNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) inRNiO3 (RfiLa). We hypothesize that the intermediate paramagnetic phase ~above TN and below TMI) in RNiO3 (R5Sm, Eu, Ho, Y! might be consequence of a self-doping effect, gradually triggering a phase segregation in electron-rich and electron-poor regions. This picture is concomitant to the temperaturedependent effect of octahedral tilting and distortion and self-trapped electrons in a polaronic medium. segregation in electron-rich and electron-poor regions. This picture is concomitant to the temperaturedependent effect of octahedral tilting and distortion and self-trapped electrons in a polaronic medium. NiO3 (R5Sm, Eu, Ho, Y! might be consequence of a self-doping effect, gradually triggering a phase segregation in electron-rich and electron-poor regions. This picture is concomitant to the temperaturedependent effect of octahedral tilting and distortion and self-trapped electrons in a polaronic medium.