Influence of oxygen isotope exchange on the ground state of manganites

Abstract

We report a study of oxygen isotope effects on low temperature specific heat, magnetization, and resistivity of La${}_{1-x}$Ca${}_x$MnO${}_3$ and (La${}_{1-y}$Pr${}_y{)}_{0.67}$Ca${}_{0.33}$MnO${}_3$. For the metallic compositions of La${}_{1-x}$Ca${}_x$MnO${}_3$ and for charge-ordered La${}_{0.5}$Ca${}_{0.5}$MnO${}_3$ no change in low temperature specific heat has been detected with ${}^{16}$O -${}^{18}$O exchange, while compounds of (La${}_{1-y}$Pr${}_y{)}_{0.67}$Ca${}_{0.33}$MnO${}_3$ (0.4<y<0.6) show a significant change in low temperature properties. The low temperature specific heat indicates a presence of the charge-ordered phase even in compositions of (La${}_{1-y}$Pr${}_y{)}_{0.67}$Ca${}_{0.33}$MnO${}_3$ which are metallic at low temperatures. We suggest that the changes induced by the oxygen isotope exchange are caused by an increase of the charge-ordered phase in ${}^{18}$O samples.

10 pages, 9 figures. submitted to Phys. Rev. B

References in corpus (4)

• Charge Ordering and Polaron Formation in the Magnetoresistive Oxide La0.7Ca0.3MnO3
• Correlated Polarons in Dissimilar Perovskite Manganites
• Nanometer-sized Regions of Charge Ordering and Charge Melting in La2/3Ca1/3MnO3 Revealed by Electron Micro-diffraction
• Evidence for novel polaronic Fermi-liquid in doped oxides

Cited by in corpus (6)

• First-order nature of the ferromagnetic phase transition in (La-Ca)MnO_3 near optimal doping
• Nanoscale magnetic structure of ferromagnet/antiferromagnet manganite multilayers
• Dynamical Mean-Field Theory of Electron-Phonon Interactions in Correlated Systems: Application to Isotope Effects on Electronic Properties
• Inhomogeneous ferrimagnetic-like behavior in Gd2/3Ca1/3MnO3 single crystals
• Disorder effects at low temperatures in La_{0.7-x}Y_{x}Ca_{0.3}MnO_{3} manganites
• Direct observation of magnetic phase coexistence and magnetization reversal in a Gd${}_{0.67}$Ca${}_{0.33}$MnO${}_3$ thin film